U.S. patent application number 14/057627 was filed with the patent office on 2014-02-13 for exposure apparatus, exposure method, and method for producing device.
This patent application is currently assigned to NIKON CORPORATION. The applicant listed for this patent is NIKON CORPORATION. Invention is credited to Hiroyuki NAGASAKA, Minoru ONDA.
Application Number | 20140043593 14/057627 |
Document ID | / |
Family ID | 35503357 |
Filed Date | 2014-02-13 |
United States Patent
Application |
20140043593 |
Kind Code |
A1 |
NAGASAKA; Hiroyuki ; et
al. |
February 13, 2014 |
EXPOSURE APPARATUS, EXPOSURE METHOD, AND METHOD FOR PRODUCING
DEVICE
Abstract
A liquid immersion exposure apparatus includes a nozzle member
having a recovery port and an opening via which an exposure beam
passes. A projection system includes a first element closest to an
image surface and a second element which is second closest to the
image surface. The first element has a first surface facing the
image surface, a second surface facing a lower surface of the
second element, an inclined outer surface extending upwardly and
radially outwardly from the first surface and facing an inner
surface of the nozzle member, and a flange portion provided above
the inclined outer surface. A support member supports the flange
portion of the first element. A substrate stage has a holder for
holding a substrate to be exposed and moves the substrate below and
relative to the nozzle member and the projection system.
Inventors: |
NAGASAKA; Hiroyuki;
(Kumagaya-shi, JP) ; ONDA; Minoru; (Ageo-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NIKON CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
NIKON CORPORATION
Tokyo
JP
|
Family ID: |
35503357 |
Appl. No.: |
14/057627 |
Filed: |
October 18, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11628507 |
Dec 5, 2006 |
|
|
|
PCT/JP05/10484 |
Jun 8, 2005 |
|
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14057627 |
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Current U.S.
Class: |
355/30 |
Current CPC
Class: |
G03F 7/70958 20130101;
G03F 7/7095 20130101; G03F 7/70341 20130101; G03F 7/70825 20130101;
G03F 7/70225 20130101; G03F 7/70316 20130101; G03F 7/70916
20130101 |
Class at
Publication: |
355/30 |
International
Class: |
G03F 7/20 20060101
G03F007/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 10, 2004 |
JP |
2004-172568 |
Claims
1. A liquid immersion exposure apparatus comprising: a nozzle
member having a recovery port and an opening via which an exposure
beam passes; a projection system having a first element closest to
an image surface and a second element which is second closest to
the image surface, the first element having (i) a first surface
facing the image surface, (ii) a second surface facing a lower
surface of the second element, (iii) an inclined outer surface
extending upwardly and radially outwardly from the first surface
and facing an inner surface of the nozzle member, and (iv) a flange
portion provided above the inclined outer surface; a support member
by which the flange portion of the first element is supported; and
a substrate stage which has a holder for holding a substrate to be
exposed and which moves the substrate below and relative to the
nozzle member and the projection system, wherein the substrate held
on the holder is exposed by projecting the exposure beam onto the
substrate via the opening of the nozzle member through an immersion
liquid between the first surface of the first element and the
substrate.
Description
[0001] This is a Division of U.S. patent application Ser. No.
11/628,507 filed Dec. 5, 2006, which is the U.S. National Phase of
PCT/JP2005/010484 filed Jun. 8, 2005. The disclosure of each of the
prior applications is hereby incorporated by reference herein in
its entirety.
TECHNICAL FIELD
[0002] The present invention relates to an exposure apparatus for
exposing a substrate through a liquid, an exposure method, and a
method for producing a device.
BACKGROUND ART
[0003] Semiconductor devices and liquid crystal display devices are
produced by means of the so-called photolithography technique in
which a pattern formed on a mask is transferred onto a
photosensitive substrate. The exposure apparatus, which is used in
the photolithography step, includes a mask stage for supporting the
mask and a substrate stage for supporting the substrate. The
pattern on the mask is transferred onto the substrate via a
projection optical system while successively moving the mask stage
and the substrate stage. In recent years, it is demanded to realize
the higher resolution of the projection optical system in order to
respond to the further advance of the higher integration of the
device pattern. As the exposure wavelength to be used is shorter,
the resolution of the projection optical system becomes higher. As
the numerical aperture of the projection optical system is larger,
the resolution of the projection optical system becomes higher.
Therefore, the exposure wavelength, which is used for the exposure
apparatus, is shortened year by year, and the numerical aperture of
the projection optical system is increased as well. The exposure
wavelength, which is dominantly used at present, is 248 nm of the
KrF excimer laser. However, the exposure wavelength of 193 nm of
the ArF excimer laser, which is shorter than the above, is also
practically used in some situations. When the exposure is
performed, the depth of focus (DOF) is also important in the same
manner as the resolution. The resolution R and the depth of focus
.delta. are represented by the following expressions
respectively.
R=k.sub.1.lamda./NA (1)
.delta.=.+-.k.sub.2.lamda./NA.sup.2 (2)
[0004] In the expressions, .lamda. represents the exposure
wavelength, NA represents the numerical aperture of the projection
optical system, and k.sub.1 and k.sub.2 represent the process
coefficients. According to the expressions (1) and (2), the
following fact is appreciated. That is, when the exposure
wavelength .lamda. is shortened and the numerical aperture NA is
increased in order to enhance the resolution R, then the depth of
focus .delta. is narrowed.
[0005] If the depth of focus .delta. is too narrowed, it is
difficult to match the substrate surface with respect to the image
plane of the projection optical system. It is feared that the focus
margin is insufficient during the exposure operation. Accordingly,
the liquid immersion method has been suggested, which is disclosed,
for example, in International Publication No. 99/49504 as a method
for substantially shortening the exposure wavelength and widening
the depth of focus. In this liquid immersion method, the space
between the lower surface of the projection optical system and the
substrate surface is filled with a liquid such as water or any
organic solvent to form a liquid immersion area so that the
resolution is improved and the depth of focus is magnified about n
times by utilizing the fact that the wavelength of the exposure
light beam in the liquid is 1/n as compared with that in the air (n
represents the refractive index of the liquid, which is about 1.2
to 1.6 in ordinary cases).
[0006] In the case of the liquid immersion exposure apparatus as
disclosed in International Publication No. 99/49504 described
above, the liquid in the liquid immersion area formed on the
substrate makes contact with the optical element which is arranged
most closely to the image plane among a plurality of elements
(optical elements) for constructing the projection optical system.
In such a situation, the following possibility arises. That is, if
the liquid in the liquid immersion area is mixed with any impurity
or the like generated, for example, from the surface of the
substrate, and the liquid in the liquid immersion area is
contaminated therewith, then the optical element, which is arranged
most closely to the image plane, may be polluted with the
contaminated liquid in the liquid immersion area. If the optical
element is polluted, any inconvenience arises, for example, such
that the light transmittance of the optical element is lowered
and/or any distribution appears in the light transmittance. As a
result, there is such a possibility that the exposure accuracy and
the measurement accuracy, which are obtained via the projection
optical system, are deteriorated.
[0007] A scanning type exposure apparatus, which exposes the
substrate with the pattern formed on the mask while synchronously
moving the mask and the substrate in the scanning direction, is
also disclosed in International Publication No. 99/49504 described
above. In the case of the scanning type exposure apparatus, it is
required to realize the high speed for the scanning velocity
(scanning speed) in order to improve, for example, the productivity
of the device. However, if the high scanning velocity is realized,
the following possibility arises. That is, it is difficult to
maintain the liquid immersion area to have a desired size.
DISCLOSURE OF THE INVENTION
Problem to be Solved by the Invention
[0008] The present invention has been made taking the foregoing
circumstances into consideration, an object of which is to provide
an exposure apparatus with which it is possible to avoid the
deterioration of the exposure accuracy and the measurement accuracy
caused by the pollution of the element (optical element), and a
method for producing a device using the exposure apparatus. Another
object of the present invention is to provide an exposure apparatus
and an exposure method in which the liquid immersion area is
maintained to be in a desired state, and a method for producing a
device using the exposure apparatus.
Means for Solving the Problem and Effect of the Invention
[0009] In order to achieve the objects as described above, the
present invention adopts the following constructions.
[0010] According to a first aspect of the present invention, there
is provided an exposure apparatus which exposes a substrate by
radiating an exposure light beam onto the substrate through a
liquid; the exposure apparatus comprising a projection optical
system which has a plurality of elements including a first element
closest to an image plane and a second element which is second
closest to the image plane with respect to the first element;
wherein the first element has a first surface which is arranged
opposite to a surface of the substrate and through which the
exposure light beam passes, and a second surface which is arranged
opposite to the second element and through which the exposure light
beam passes; the first element and the second element are supported
in a substantially stationary state with respect to an optical axis
of the projection optical system; a space between the second
element and the second surface of the first element is filled with
a second liquid so that only a partial area, which includes an area
of the second surface of the first element through which the
exposure light beam passes, serves as a liquid immersion area; and
the exposure light beam is radiated onto the substrate to expose
the substrate through a first liquid on a side of the first surface
of the first element and the second liquid on a side of the second
surface.
[0011] According to the present invention, the space between the
substrate and the first surface of the first element is filled with
the first liquid, and the space between the second element and the
second surface of the first element is filled with the second
liquid. Accordingly, the substrate can be exposed satisfactorily in
a state in which the large image side numerical aperture of the
projection optical system PL is secured. On the other hand, when
the first liquid, which is on the side of the first surface, makes
contact with the substrate, there is such a high possibility that
the side of the first surface of the first element may be polluted.
However, the first element can be constructed to be easily
exchangeable, because each of the side of the first surface of the
first element and the side of the second surface of the first
element is filled with the liquid. Therefore, only the polluted
first element can be exchanged with another clean element. The
exposure and the measurement can be performed satisfactorily via
the liquids and the projection optical system provided with the
clean first element. The second liquid locally forms the liquid
immersion area in only the partial area, including the area through
which the exposure light beam passes, of the second surface of the
first element. Accordingly, the second liquid can be prevented from
any leakage from the circumference of the second surface of the
first element. Therefore, it is possible to avoid the deterioration
of any mechanical part or the like disposed around the first
element, which would be otherwise caused by the leaked second
liquid. Further, it is possible to avoid the inflow of the liquid,
for example, into the support section for supporting the first
element, by locally forming the liquid immersion area of the second
liquid on the second surface of the first element. It is possible
to avoid the deterioration of the support section. The second
liquid makes no contact, for example, with the support section for
supporting the element, because the second liquid locally forms the
liquid immersion area on the second surface. Therefore, it is
possible to avoid the inconvenience which would be otherwise
caused, for example, such that the second liquid for forming the
liquid immersion area is mixed with any impurity generated from the
support section or the like. Therefore, the exposure process and
the measurement process can be performed satisfactorily in a state
in which the cleanness of the second liquid is maintained.
[0012] The first element, which is referred to in the present
invention, may be a transparent member having no refractive power
(for example, a parallel flat plate or plane parallel plate). For
example, even when the transparent member, which is arranged most
closely to the image plane, does not contribute to the image
formation performance of the projection optical system at all, the
transparent member is regarded as the first element. The first
element and the second element, which are referred to in the
present invention, are supported in the substantially stationary
state with respect to the optical axis (exposure light beam) of the
projection optical system. However, even when at least one of the
first element and the second element is supported finely movably in
order to adjust the posture and the position thereof, it is
regarded that the element is "supported in the substantially
stationary state".
[0013] According to a second aspect of the present invention, there
is provided an exposure apparatus which exposes a substrate by
radiating an exposure light beam onto the substrate through a
liquid; the exposure apparatus comprising a projection optical
system which has a plurality of elements including a first element
closest to an image plane and a second element which is second
closest to the image plane with respect to the first element;
wherein the first element has a first surface which is arranged
opposite to a surface of the substrate and through which the
exposure light beam passes, and a second surface which is arranged
opposite to the second element and through which the exposure light
beam passes; an outer diameter of a surface of the second element
opposed to the first element is smaller than an outer diameter of
the second surface of the first element; the first element and the
second element are supported in a substantially stationary state
with respect to an optical axis of the projection optical system;
and the exposure light beam is radiated onto the substrate to
expose the substrate through a first liquid on a side of the first
surface of the first element and a second liquid on a side of the
second surface.
[0014] According to the present invention, the outer diameter of
the opposing surface of the second element opposed to the first
element is smaller than the outer diameter of the second surface of
the first element. Accordingly, the liquid immersion area, which
has the size corresponding to the surface of the second element,
can be formed locally on the second surface of the first element,
while covering the opposing surface with the second liquid.
Therefore, the second liquid can be prevented from any leakage from
the circumference of the second surface of the first element. It is
possible to avoid the deterioration of any mechanical part or the
like disposed around the first element, which would be otherwise
caused by the leaked second liquid. Further, it is possible to
avoid the inflow of the liquid, for example, into the support
section for supporting the first element, by locally forming the
liquid immersion area of the second liquid on the second surface of
the first element. It is possible to avoid the deterioration of the
support section. The second liquid makes no contact, for example,
with the support section for supporting the element, because the
second liquid locally forms the liquid immersion area on the second
surface. Therefore, it is possible to avoid the inconvenience which
would be otherwise caused, for example, such that the second liquid
for forming the liquid immersion area is mixed with any impurity
generated from the support section or the like. Therefore, it is
possible to maintain the cleanness of the second liquid. When the
exposure light beam is radiated onto the substrate via the second
liquid of the liquid immersion area formed locally on the second
surface and the first liquid of the liquid immersion area formed on
the side of the first surface, the substrate can be exposed
satisfactorily in the state in which the large image side numerical
aperture of the projection optical system is secured. Each of the
side of the first surface of the first element and the side of the
second surface of the first element is filled with the liquid.
Accordingly, the first element can be constructed to be easily
exchangeable. Therefore, only the polluted first element can be
exchanged with another clean element. The exposure and the
measurement can be performed satisfactorily via the liquids and the
projection optical system provided with the clean first
element.
[0015] The first element, which is referred to in the present
invention, may be a transparent member having no refractive power
(for example, a parallel flat plate or plane parallel plate). For
example, even when the transparent member, which is arranged most
closely to the image plane, does not contribute to the image
formation performance of the projection optical system at all, the
transparent member is regarded as the first element and as a part
of the projection optical system. The first element and the second
element, which are referred to in the present invention, are
supported in the substantially stationary state with respect to the
optical axis (exposure light beam) of the projection optical
system. However, even when at least one of the first element and
the second element is supported finely movably in order to adjust
the posture and the position thereof, it is regarded that the
element is "supported in the substantially stationary state".
[0016] According to a third aspect of the present invention, there
is provided an exposure apparatus which exposes a substrate by
radiating an exposure light beam onto the substrate through a first
liquid; the exposure apparatus comprising a projection optical
system which includes a plurality of elements and which has a first
element closest to an image plane and a second element which is
second closest to the image plane with respect to the first
element; and a first liquid immersion mechanism which supplies the
first liquid; wherein the first element has a first surface which
is arranged opposite to a surface of the substrate and through
which the exposure light beam passes, and a second surface which is
arranged opposite to the second element and which is substantially
in parallel to the first surface; an outer diameter of the second
surface of the first element is greater than an outer diameter of
the first surface of the first element; and the exposure light beam
is radiated onto the substrate to expose the substrate through the
first liquid between the first element and the substrate.
[0017] According to the present invention, the outer diameter of
the second surface of the first element is greater than the outer
diameter of the first surface. Accordingly, when the first element
is supported by a support section, the support section, which
supports the first element, can be provided at a position (end
portion of the second surface) away from the optical axis of the
first element. Therefore, it is possible to avoid the interference
between the support section and any member or equipment or the like
arranged around the first element, and it is possible to improve
the degree of freedom of the design and the degree of freedom of
the arrangement of the member or the equipment or the like.
Further, it is possible to decrease the size of the liquid
immersion area formed between the first surface and the substrate
by the first liquid immersion mechanism, because the outer diameter
of the first surface of the first element is sufficiently smaller
than that of the second surface.
[0018] The first element, which is referred to in the present
invention, may be a transparent member having no refractive power
(for example, a parallel flat plate or plane parallel plate). For
example, even when the transparent member, which is arranged most
closely to the image plane, does not contribute to the image
formation performance of the projection optical system at all, the
transparent member is regarded as the first element and as a part
of the projection optical system.
[0019] According to a fourth aspect of the present invention, there
is provided an exposure apparatus which exposes a substrate by
radiating an exposure light beam onto the substrate through a first
liquid; the exposure apparatus comprising a first liquid immersion
mechanism which provides the first liquid onto the substrate; and a
projection optical system which has a plurality of elements
including a first element closest to an image plane and a second
element which is second closest to the image plane with respect to
the first element; wherein the first element is arranged so that a
first surface of the first element is opposed to a surface of the
substrate, and a second surface of the first element is opposed to
the second element; a distance between the first surface and the
second surface of the first element on an optical axis of the
projection optical system is not less than 15 mm; and the exposure
light beam is radiated onto the substrate to expose the substrate
through the first liquid on a side of the first surface of the
first element.
[0020] According to the present invention, the distance between the
first surface and the second surface of the first element, i.e.,
the thickness of the first element is not less than 15 mm, and thus
the first element is thick. Therefore, the degree of freedom of the
position is increased for the member and the equipment or the like
arranged around the first element. Accordingly, it is possible to
avoid the interference between the support section and the member
or equipment or the like arranged around the first element. As a
result, it is possible to improve the degree of freedom of the
design of the member or the equipment or the like. Accordingly, the
support section, which supports the first element, can be provided
at a position away from the optical axis of the first element. In
particular, it is noted that the size of the liquid immersion area
of the first liquid can be decreased by improving the degree of
freedom of the design and the arrangement of the liquid immersion
mechanism for forming the liquid immersion area of the first
liquid. Further, the second liquid may be supplied also to the
space between the first element and the second element without
being limited to the first liquid supplied to the space between the
first element and the substrate. When the exposure light beam is
radiated onto the substrate through the first liquid and the second
liquid, the substrate can be exposed satisfactorily in the state in
which the large image side numerical aperture of the projection
optical system is secured. The first element can be constructed to
be easily exchangeable, because each of the side of the first
surface of the first element and the side of the second surface of
the first element is filled with the liquid. Therefore, only the
polluted first element can be exchanged with another clean element.
The exposure and the measurement can be performed satisfactorily
via the liquid and the projection optical system provided with the
clean first element. When the first element is not less than 15 mm,
the change of the shape of the first element, which would be
otherwise caused by the force received from the liquid, can be
suppressed. Therefore, it is possible to maintain the high image
formation performance of the projection optical system.
[0021] The first element, which is referred to in the present
invention, may be a transparent member having no refractive power
(for example, a parallel flat plate or plane parallel plate). For
example, even when the transparent member, which is arranged most
closely to the image plane, does not contribute to the image
formation performance of the projection optical system at all, the
transparent member is regarded as the first element and as a part
of the projection optical system.
[0022] According to a fifth aspect of the present invention, there
is provided an exposure apparatus which exposes a substrate by
radiating an exposure light beam onto the substrate through a first
liquid; the exposure apparatus comprising a first liquid immersion
mechanism which provides the first liquid onto the substrate; and a
projection optical system which has a plurality of elements
including a first element closest to an image plane and a second
element which is second closest to the image plane with respect to
the first element; wherein the first element has a first surface
which is arranged opposite to a surface of the substrate and
through which the exposure light beam passes, and a second surface
which is arranged opposite to the second element and through which
the exposure light beam passes; a distance between the first
surface and the second surface of the first element on an optical
axis of the projection optical system is greater than a distance
between the first surface of the first element and the surface of
the substrate on the optical axis of the projection optical system;
and the exposure light beam is radiated onto the substrate to
expose the substrate through the first liquid between the substrate
and the first element and a second liquid between the second
element and the first element.
[0023] According to the present invention, the substrate can be
exposed satisfactorily in a state in which the large image side
numerical aperture of the projection optical system is secured, by
radiating the exposure light beam onto the substrate through the
first liquid and the second liquid. The first element is thick, and
thus the support section, which supports the first element, can be
provided at a position away from the optical axis. The degree of
freedom is increased, for example, for the arrangement of the
member and the equipment arranged around the first element.
Further, it is possible to suppress the change of the shape of the
first element, which would be otherwise caused by the force
received from the liquid. Therefore, it is possible to maintain the
high image formation performance of the projection optical
system.
[0024] According to a sixth aspect of the present invention, there
is provided an exposure apparatus which exposes a substrate by
radiating an exposure light beam onto the substrate through a first
liquid; the exposure apparatus comprising a first liquid immersion
mechanism which provides the first liquid onto the substrate to
form a liquid immersion area of the first liquid on a part of the
substrate; and a projection optical system which has a plurality of
elements including a first element closest to an image plane and a
second element which is second closest to the image plane with
respect to the first element; wherein the first element has a first
surface which is arranged opposite to a surface of the substrate
and through which the exposure light beam passes, and a second
surface which is arranged opposite to the second element and
through which the exposure light beam passes; the first liquid
immersion mechanism has a flat liquid contact surface which is
arranged opposite to the surface of the substrate, the liquid
contact surface being arranged to surround an optical path for the
exposure light beam between the substrate and the first surface of
the first element; and the exposure light beam is radiated onto the
substrate to expose the substrate through the first liquid between
the substrate and the first element and the second liquid between
the second element and the first element.
[0025] According to the present invention, the substrate can be
exposed satisfactorily in a state in which the large image side
numerical aperture of the projection optical system is secured, by
radiating the exposure light beam onto the substrate through the
first liquid and the second liquid. The flat liquid contact surface
is arranged opposite to the surface of the substrate around the
optical path for the exposure light beam, between the first element
and the substrate. Therefore, it is possible to continuously fill
the optical path between the first element and the substrate with
the first liquid.
[0026] According to a seventh aspect of the present invention,
there is provided an exposure method for exposing a substrate by
radiating an exposure light beam onto the substrate via a liquid
and a projection optical system including a first element closest
to an image plane and a second element which is second closest to
the image plane with respect to the first element; wherein a first
surface of the first element, which is opposed to the substrate, is
smaller than a second surface of the first element which is opposed
to the second element; and a surface of the second element, which
is opposed to the first element, is smaller than the second surface
of the first element; the exposure method comprising providing a
first liquid to a space between the substrate and the first
element; providing a second liquid to a space between the first
element and the second element; and exposing the substrate by
radiating the exposure light beam onto the substrate through the
first liquid and the second liquid. According to the exposure
method of the present invention, the space between the first
element and the second element can be reliably filled with the
second liquid. The exposure light beam is radiated onto the
substrate through the first liquid and the second liquid, and thus
the substrate can be satisfactorily exposed in a state in which the
large image side numerical aperture of the projection optical
system is secured.
[0027] According to still another aspect of the present invention,
there is provided a method for producing a device, comprising using
the exposure apparatus or the exposure method described above.
According to the present invention, it is possible to
satisfactorily maintain the exposure accuracy and the measurement
accuracy. Therefore, it is possible to produce the device having
the desired performance.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 shows a schematic arrangement illustrating an
exposure apparatus according to an embodiment of the present
invention.
[0029] FIG. 2 shows a schematic perspective view illustrating those
disposed in the vicinity of a nozzle member.
[0030] FIG. 3 shows a perspective view illustrating the nozzle
member as viewed from a lower position.
[0031] FIG. 4 shows a side sectional view illustrating those
disposed in the vicinity of the nozzle member.
[0032] FIGS. 5(a) and 5(b) illustrate a second liquid immersion
mechanism.
[0033] FIG. 6 shows a plan view illustrating a second surface of a
first element.
[0034] FIG. 7 illustrates the operation for recovering the second
liquid by the second liquid immersion mechanism.
[0035] FIGS. 8(a) and 8(b) schematically illustrate the operation
for recovering the liquid by a first liquid immersion mechanism
according to the present invention.
[0036] FIGS. 9(a) and 9(b) schematically show a comparative example
of the operation for recovering the liquid.
[0037] FIG. 10 schematically shows a modified embodiment of a first
element.
[0038] FIG. 11 shows a perspective view illustrating a modified
embodiment of the nozzle member as viewed from a lower
position.
[0039] FIG. 12 shows a sectional view illustrating major parts to
depict another embodiment of the present invention.
[0040] FIG. 13 shows a sectional view illustrating major parts to
depict another embodiment of the present invention.
[0041] FIG. 14 shows a sectional view illustrating major parts to
depict another embodiment of the present invention.
[0042] FIG. 15 shows a flow chart illustrating exemplary steps of
producing a semiconductor device.
[0043] FIG. 16 illustrates the operation for recovering the liquid
by a first liquid recovery mechanism in another embodiment of the
present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0044] The present invention will be explained below with reference
to the drawings. However, the present invention is not limited
thereto.
[0045] FIG. 1 shows a schematic arrangement illustrating an
exposure apparatus according to an embodiment of the present
invention. With reference to FIG. 1, the exposure apparatus EX
includes a mask stage MST which is movable while holding a mask M,
a substrate stage PST which is movable while holding a substrate P,
an illumination optical system IL which illuminates, with an
exposure light beam EL, the mask M held by the mask stage MST, a
projection optical system PL which performs the projection exposure
for the substrate P held by the substrate stage PST with an image
of a pattern of the mask M illuminated with the exposure light beam
EL, and a control unit CONT which integrally controls the operation
of the entire exposure apparatus EX.
[0046] The exposure apparatus EX of the embodiment of the present
invention is a liquid immersion exposure apparatus to which the
liquid immersion method is applied in order that the exposure
wavelength is substantially shortened to improve the resolution and
the depth of focus is substantially widened. The exposure apparatus
EX includes a first liquid immersion mechanism 1 which fills, with
the first liquid LQ1, the space between the substrate P and a lower
surface T1 of a first optical element LS1 closest to the image
plane of the projection optical system PL, among a plurality of
optical elements LS1 to LS7 for constructing the projection optical
system PL. The substrate P is provided on the side of the image
plane of the projection optical system PL. The lower surface T1 of
the first optical element LS1 is arranged opposite to the surface
of the substrate P. The first liquid immersion mechanism 1 includes
a first liquid supply mechanism 10 which supplies the first liquid
LQ1 to the space between the substrate P and the lower surface T1
of the first optical element LS1, and a first liquid recovery
mechanism 20 which recovers the first liquid LQ1 supplied by the
first liquid supply mechanism 10. The operation of the first liquid
immersion mechanism 1 is controlled by the control unit CONT.
[0047] The exposure apparatus EX includes a second liquid immersion
mechanism 2 which fills, with the second liquid LQ2, the space
between the first optical element LS1 and the second optical
element LS2 which is the next closest to the image plane of the
projection optical system PL with respect to the first optical
element LS1. The second optical element LS2 is arranged over
(above) the first optical element LS1. That is, the second optical
element LS2 is arranged on the side of the light-incident surface
of the first optical element LS1. The upper surface T2 of the first
optical element LS1 is arranged opposite to the lower surface T3 of
the second optical element LS2. The second liquid immersion
mechanism 2 includes a second liquid supply mechanism 30 which
supplies the second liquid LQ2 to the space between the first
optical element LS1 and the second optical element LS2, and a
second liquid recovery mechanism 40 which recovers the second
liquid LQ2 supplied by the second liquid supply mechanism 30. The
operation of the second liquid immersion mechanism 2 is controlled
by the control unit CONT.
[0048] In this embodiment, the first optical element LS1 is a
parallel flat plate having no refractive power through which the
exposure light beam EL is transmissive. The lower surface T1 and
the upper surface T2 of the first optical element LS1 are
substantially in parallel to each other. The image formation
characteristics including, for example, the aberration are set
within predetermined allowable ranges for the projection optical
system PL including the first optical element LS1.
[0049] In this embodiment, the space (first space) K1 between the
first optical element LS1 and the substrate P and the space (second
space) K2 between the first optical element LS1 and the second
optical element LS2 are spaces which are independent from each
other. The control unit CONT can independently perform the supply
operation and the recovery operation for the first liquid LQ1 with
respect to the first space K1 by the first liquid immersion
mechanism 1 and the supply operation and the recovery operation for
the second liquid LQ2 with respect to the second space K2 by the
second liquid immersion mechanism 2. The liquid (LQ1, LQ2) neither
comes in nor goes out from one to the other of the first space K1
and the second space K2.
[0050] The exposure apparatus EX is operated as follows at least
during the period in which the image of the pattern of the mask M
is projected onto the substrate P. That is, the space between the
first optical element LS1 and the substrate P arranged on the image
plane side thereof is filled with the first liquid LQ1 by using the
first liquid immersion mechanism 1 to form the first liquid
immersion area LR1, and the space between the first optical element
LS1 and the second optical element LS2 is filled with the second
liquid LQ2 by using the second liquid immersion mechanism 2 to form
the second liquid immersion area LR2. In this embodiment, the
exposure apparatus EX adopts the local liquid immersion system
wherein the first liquid immersion area LR1, which is greater than
the projection area AR and which is smaller than the substrate P,
is locally formed on a part of the substrate P, the part including
the projection area AR of the projection optical system PL. In this
embodiment, the exposure apparatus EX locally forms the second
liquid immersion area LR2 of the second liquid LQ2 in only a
partial area, including the area AR', of the upper surface T2 of
the first optical element LS1 through which the exposure light beam
EL passes. The exposure apparatus EX performs the projection
exposure for the substrate P with the pattern of the mask M such
that the exposure light beam EL, which has passed through the mask
M, is radiated onto the substrate P via the projection optical
system PL, the second liquid LQ2 in the second liquid immersion
area LR2, and the first liquid LQ1 in the first liquid immersion
area LR1.
[0051] A nozzle member 70, which will be described in detail later
on, is arranged in the vicinity of the image plane of the
projection optical system PL, specifically in the vicinity of the
optical element LS1 disposed at the end on the image plane side of
the projection optical system PL. The nozzle member 70 is an
annular member which is provided to surround the end portion of the
projection optical system PL over (above) the substrate P
(substrate stage PST). In this embodiment, the nozzle member 70
constructs a part of the first liquid immersion mechanism 1.
[0052] The embodiment of the present invention will be explained as
exemplified by a case of the use of the scanning type exposure
apparatus (so-called scanning stepper) as the exposure apparatus EX
in which the substrate P is exposed with the pattern formed on the
mask M while synchronously moving the mask M and the substrate P in
mutually different directions (opposite directions) in the scanning
directions. In the following explanation, the Z axis direction is
the direction which is coincident with the optical axis AX of the
projection optical system PL, the X axis direction is the
synchronous movement direction (scanning direction) for the mask M
and the substrate P in the plane perpendicular to the Z axis
direction, and the Y axis direction is the direction (non-scanning
direction) perpendicular to the Z axis direction and the X axis
direction. The directions of rotation (inclination) about the X
axis, the Y axis, and the Z axis are designated as .theta.X,
.theta.Y, and .theta.Z directions respectively.
[0053] The exposure apparatus EX includes a base BP which is
provided on the floor surface, and a main column 9 which is
installed on the base BP. The main column 9 is formed with an upper
step 7 and a lower step 8 which protrude inwardly. The illumination
optical system IL illuminates, with the exposure light beam EL, the
mask M supported by the mask stage MST. The illumination optical
system IL is supported by a support frame 3 which is fixed to the
upper portion of the main column 9.
[0054] The illumination optical system IL includes, for example, an
exposure light source which radiates the exposure light beam EL, an
optical integrator which uniformizes the illuminance of the
exposure light beam EL radiated from the exposure light source, a
condenser lens which collects the exposure light beam EL emitted
from the optical integrator, a relay lens system, and a variable
field diaphragm which sets the illumination area on the mask M
formed by the exposure light beam EL to be slit-shaped. The
predetermined illumination area on the mask M is illuminated with
the exposure light beam EL having a uniform illuminance
distribution by the illumination optical system IL. Those usable as
the exposure light beam EL radiated from the exposure light source
include, for example, emission lines (g-ray, h-ray, i-ray)
radiated, for example, from a mercury lamp, far ultraviolet light
beams (DUV light beams) such as the KrF excimer laser beam
(wavelength: 248 nm), and vacuum ultraviolet light beams (VUV light
beams) such as the ArF excimer laser beam (wavelength: 193 nm) and
the F.sub.2 laser beam (wavelength: 157 nm). In this embodiment,
the ArF excimer laser beam is used.
[0055] In this embodiment, pure water is used for the first liquid
LQ1 to be supplied from the first liquid supply mechanism 10 and
the second liquid LQ2 to be supplied from the second liquid supply
mechanism 30. That is, in this embodiment, the first liquid LQ1 and
the second liquid LQ2 are the same liquid. Those capable of being
transmitted through pure water are not limited to the ArF excimer
laser beam, and also include the emission line (g-ray, h-ray,
i-ray) radiated, for example, from a mercury lamp and the far
ultraviolet light beam (DUV light beam) such as the KrF excimer
laser beam (wavelength: 248 nm).
[0056] The mask stage MST is movable while holding the mask M. The
mask stage MST holds the mask M by the vacuum attraction (or the
electrostatic attraction). A plurality of gas bearings (air
bearings) 85, which are non-contact bearings, are provided on the
lower surface of the mask stage MST. The mask stage MST is
supported in a non-contact manner by the air bearings 85 with
respect to the upper surface (guide surface) of a mask surface
plate (mask base plate) 4. Openings MK1, MK2, through which the
image of the pattern of the mask M passes, are formed at central
positions of the mask stage MST and the mask surface plate 4
respectively. The mask surface plate 4 is supported by the upper
step 7 of the main column 9 via an anti-vibration unit 86. That is,
in this arrangement, the mask stage MST is supported by the main
column 9 (upper step 7) via the anti-vibration unit 86 and the mask
surface plate 4. The mask surface plate 4 and the main column 9 are
isolated from each other in terms of the vibration by the
anti-vibration unit 86 so that the vibration of the main column 9
is not transmitted to the mask surface plate 4 which supports the
mask stage MST.
[0057] The mask stage MST is movable two-dimensionally in the plane
perpendicular to the optical axis AX of the projection optical
system PL, i.e., in the XY plane, and it is finely rotatable in the
.theta.Z direction on the mask surface plate 4 in a state in which
the mask M is held in accordance with the driving of the mask
stage-driving unit MSTD including a linear motor or the like
controlled by the control unit CONT. The mask stage MST is movable
at a designated scanning velocity in the X axis direction. The mask
stage MST has a movement stroke in the X axis direction to such an
extent that the entire surface of the mask M can traverse at least
the optical axis AX of the projection optical system PL.
[0058] A movement mirror 81, which is movable together with the
mask stage MST, is provided on the mask stage MST. A laser
interferometer 82 is provided at a position opposed to the movement
mirror 81. The position in the two-dimensional direction and the
angle of rotation in the .theta.Z direction (including the angles
of rotation in the .theta.X and .theta.Y directions in some cases)
of the mask M on the mask stage MST are measured in real-time by
the laser interferometer 82. The result of the measurement
performed by the laser interferometer 82 is outputted to the
control unit CONT. The control unit CONT drives the mask
stage-driving unit MSTD on the basis of the result of the
measurement obtained by the laser interferometer 82 to thereby
control the position of the mask M held by the mask stage MST.
[0059] The projection optical system PL projects the pattern on the
mask M onto the substrate P at a predetermined projection
magnification .beta. to perform the exposure. The projection
optical system PL is constructed of the plurality of optical
elements LS1 to LS7 including the first optical element LS1 which
is provided at the end portion on the side of the substrate P. The
plurality of optical elements LS1 to LS7 are supported by the
barrel PK. In this embodiment, the projection optical system PL is
the reduction system in which the projection magnification .beta.
is, for example, 1/4, 1/5, or 1/8. The projection optical system PL
may be any one of the 1.times. magnification system and the
magnifying system. The projection optical system PL may be any one
of the cata-dioptric system including dioptric and catoptric
elements, the dioptric system including no catoptric element, and
the catoptric system including no dioptric element. The exposure
light beam EL, which is radiated from the illumination optical
system IL, comes into the projection optical system PL from the
side of the object plane, and the exposure light beam passes
through the plurality of optical elements LS7 to LS1. After that,
the exposure light beam EL outgoes from the side of the image plane
of the projection optical system PL, and the exposure light beam EL
arrives at the surface of the substrate P. Specifically, the
exposure light beam EL passes through the plurality of optical
elements LS7 to LS3 respectively, and then the exposure light beam
EL passes through the predetermined area of the upper surface T4 of
the second optical element LS2. Then, the exposure light beam EL
passes through the predetermined area of the lower surface T3 of
the second optical element LS2, and then the exposure light beam EL
comes into the second liquid immersion area LR2. The exposure light
beam EL, which has passed through the second liquid immersion area
LR2, passes through the predetermined area of the upper surface T2
of the first optical element LS1, and then the exposure light beam
EL passes through the predetermined area of the lower surface T1 of
the first optical element LS1. Then, the exposure light beam EL
comes into the first liquid immersion area LR1, and then the
exposure light beam EL arrives at the surface of the substrate
P.
[0060] A flange PF is provided at the outer circumference of the
barrel PK which holds the projection optical system PL. The
projection optical system PL is supported by a barrel surface plate
(barrel base plate) 5 via the flange PF. The barrel surface plate 5
is supported by the lower step 8 of the main column 9 via an
anti-vibration unit 87. That is, in this arrangement, the
projection optical system PL is supported by the main column 9
(lower step 8) via the anti-vibration unit 87 and the barrel
surface plate 5. The barrel surface plate 5 and the main column 9
are isolated from each other in terms of the vibration by the
anti-vibration unit 87 so that the vibration of the main column 9
is not transmitted to the barrel surface plate 5 which supports the
projection optical system PL.
[0061] The substrate stage PST is movable while supporting a
substrate holder PH which holds the substrate P. The substrate
holder PH holds the substrate P by, for example, the vacuum
attraction. A plurality of gas bearings (air bearings) 88, which
are non-contact bearings, are provided on the lower surface of the
substrate stage PST. The substrate stage PST is supported in a
non-contact manner with respect to the upper surface (guide
surface) of a substrate surface plate (substrate base plate) 6 by
the air bearings 88. The substrate surface plate 6 is supported on
the base BP via an anti-vibration unit 89. The substrate surface
plate 6, the main column 9, and the base BP (floor surface) are
isolated from one another in terms of the vibration by the
anti-vibration unit 89 so that the vibration of the base BP (floor
surface) and/or the main column 9 is not transmitted to the
substrate surface plate 6 which supports the substrate stage
PST.
[0062] The substrate stage PST is movable two-dimensionally in the
XY plane, and it is finely rotatable in the .theta.Z direction on
the substrate surface plate 6 in a state in which the substrate P
is held via the substrate holder PH in accordance with the driving
of the substrate stage-driving unit PSTD including, for example, a
linear motor controlled by the control unit CONT. Further, the
substrate stage PST is also movable in the Z axis direction, the
.theta.X direction, and the .theta.Y direction.
[0063] A movement mirror 83, which is movable together with the
substrate stage PST with respect to the projection optical system
PL, is provided on the substrate stage PST. A laser interferometer
84 is provided at a position opposed to the movement mirror 83. The
angle of rotation and the position in the two-dimensional direction
of the substrate P on the substrate stage PST are measured in
real-time by the laser interferometer 84. Although not shown, the
exposure apparatus EX is provided with a focus/leveling detecting
system which detects the information about the position of the
surface of the substrate P supported by the substrate stage PST.
Those adoptable as the focus/leveling detecting system include, for
example, the oblique incidence system in which the detecting light
beam is radiated in an oblique direction onto the surface of the
substrate P, and the system in which the capacitance type sensor is
used. The focus/leveling detecting system detects the information
about the position in the Z axis direction of the surface of the
substrate P and the information about the inclination in the
.theta.X and .theta.Y directions of the substrate P through or not
through the first liquid LQ1. In the case of the focus/leveling
detecting system which detects the surface information about the
surface of the substrate P through or not through the liquid LQ1,
the surface information about the surface of the substrate P may be
detected at any position away from the projection optical system
PL. An exposure apparatus, which detects the surface information
about the surface of the substrate P at any position away from the
projection optical system PL, is disclosed, for example, in U.S.
Pat. No. 6,674,510, contents of which are incorporated herein by
reference within a range of permission of the domestic laws and
ordinances of the state designated or selected in this
international application.
[0064] The result of the measurement performed by the laser
interferometer 84 is outputted to the control unit CONT. The result
of the detection performed by the focus/leveling detecting system
is also outputted to the control unit CONT. The control unit CONT
drives the substrate stage-driving unit PSTD on the basis of the
result of the detection performed by the focus/leveling detecting
system to control the focus position and the angle of inclination
of the substrate P so that the surface of the substrate P is
adjusted to match the image plane of the projection optical system
PL. Further, the substrate P is subjected to the position control
in the X axis direction and the Y axis direction on the basis of
the result of the measurement performed by the laser interferometer
84.
[0065] A recess 90 is provided on the substrate stage PST. The
substrate holder PH for holding the substrate P is arranged in the
recess 90. The upper surface 91 of the substrate stage PST except
for the recess 90 is a flat surface (flat portion) which has
substantially the same height as that of (is flush with) the
surface of the substrate P held by the substrate holder PH. In this
embodiment, the upper surface of the movement mirror 83 is also
provided to be substantially flush with the upper surface 91 of the
substrate stage PST.
[0066] Substantially no difference in height appears outside the
edge portion of the substrate P even when the edge area of the
substrate P is subjected to the liquid immersion exposure, because
the upper surface 91, which is substantially flush with the surface
of the substrate P, is provided around the substrate P. Therefore,
the liquid immersion area LR1 can be satisfactorily formed by
retaining the liquid LQ on the image plane side of the projection
optical system PL. It is also allowable that any difference in
height is present between the surface of the substrate P and the
upper surface 91 of the substrate stage PST provided that the
liquid immersion area LR1 can be maintained. A gap of about 0.1 to
2 mm is provided between the edge portion of the substrate P and
the flat surface (upper surface) 91 provided around the substrate
P. However, the liquid LQ scarcely flows into the gap owing to the
surface tension of the liquid LQ. Even when the exposure is
performed for the portion in the vicinity of the circumferential
edge of the substrate P, it is possible to retain the liquid LQ
under the projection optical system PL by the aid of the upper
surface 91.
[0067] The first liquid supply mechanism 10 of the first liquid
immersion mechanism 1 is provided to supply the first liquid LQ1 to
the first space K1 between the substrate P and the first optical
element LS1 of the projection optical system PL. The first liquid
supply mechanism 10 includes a first liquid supply section 11 which
is capable of feeding the first liquid LQ1, and a first supply tube
13 which has one end connected to the first liquid supply section
11. The other end of the first supply tube 13 is connected to the
nozzle member 70. In this embodiment, the first liquid supply
mechanism 10 supplies pure water. The first liquid supply section
11 includes, for example, a pure water-producing unit, and a
temperature-adjusting unit which adjusts the temperature of the
first liquid (pure water) LQ1 to be supplied. It is also allowable
to use a pure water-producing unit (utility power or power usage)
of a factory in which the exposure apparatus EX is installed,
instead of providing any pure water-producing unit for the exposure
apparatus EX, provided that a predetermined quality condition is
satisfied. The operation of the first liquid supply mechanism 10
(first liquid supply section 11) is controlled by the control unit
CONT. In order to form the first liquid immersion area LR1 on the
substrate P, the first liquid supply mechanism 10 supplies a
predetermined amount of the first liquid LQ1 onto the substrate P
arranged on the side of the image plane of the projection optical
system PL under the control of the control unit CONT.
[0068] A flow rate controller 16 called "mass flow controller",
which controls the liquid amount per unit time to be fed from the
first liquid supply section 11 and supplied to the image plane side
of the projection optical system PL, is provided at an intermediate
position of the first supply tube 13. The control of the liquid
supply amount by the flow rate controller 16 is performed in
accordance with the instruction signal supplied from the control
unit CONT.
[0069] The first liquid recovery mechanism 20 of the first liquid
immersion mechanism 1 recovers the first liquid LQ1 from the side
of the image plane of the projection optical system PL. The first
liquid recovery mechanism 20 includes a first liquid recovery
section 21 which is capable of recovering the first liquid LQ1, and
a first recovery tube 23 which has one end connected to the first
liquid recovery section 21. The other end of the first recovery
tube 23 is connected to the nozzle member 70. The first liquid
recovery section 21 includes, for example, a vacuum system (suction
unit) such as a vacuum pump, and a gas/liquid separator which
separates the recovered first liquid LQ1 from the gas. It is also
allowable that all of the components including, for example, the
vacuum system and the gas/liquid separator are not provided for the
exposure apparatus EX but to use the equipment of a factory or the
like in which the exposure apparatus EX is arranged, in place of at
least a part or parts of the components as described above. The
operation of the first liquid recovery mechanism 20 (first liquid
recovery section 21) is controlled by the control unit CONT. In
order to form the first liquid immersion area LR1 on the substrate
P, the first liquid recovery mechanism 20 recovers a predetermined
amount of the first liquid LQ1 from the surface of the substrate P
supplied from the first liquid supply mechanism 10 in accordance
with the control of the control unit CONT.
[0070] The second liquid supply mechanism 30 of the second liquid
immersion mechanism 2 supplies the second liquid LQ2 to the second
space K2 between the second optical element LS2 and the first
optical element LS1 of the projection optical system PL. The second
liquid supply mechanism 30 includes a second liquid supply section
31 which is capable of feeding the second liquid LQ2, and a second
supply tube 33 which has one end connected to the second liquid
supply section 31. The other end of the second supply tube 33 is
connected to the second space K2 disposed between the first optical
element LS1 and the second optical element LS2, for example, via
the supply flow passage (34) as described later on. The second
liquid supply mechanism 30 supplies pure water in the same manner
as the first liquid supply mechanism 10. The second liquid supply
section 31 includes, for example, a pure water-producing unit, and
a temperature-adjusting unit which adjusts the temperature of the
second liquid (pure water) LQ2 to be supplied. It is also allowable
to use a pure water-producing unit (utility power or power usage)
of a factory in which the exposure apparatus EX is installed,
instead of providing any pure water-producing unit for the exposure
apparatus EX. The operation of the second liquid supply mechanism
30 (second liquid supply section 31) is controlled by the control
unit CONT. In order to form the second liquid immersion area LR2 on
the upper surface T2 of the first optical element LS1, the second
liquid supply mechanism 30 supplies a predetermined amount of the
second liquid LQ2 onto the upper surface T2 of the first optical
element LS1 in accordance with the control of the control unit
CONT.
[0071] The pure water-producing unit may be used commonly for both
of the first liquid immersion mechanism 1 and the second liquid
immersion mechanism.
[0072] A mass flow controller, which controls the liquid amount per
unit time fed from the second liquid supply section 31 and supplied
to the second space K2, may be also provided at an intermediate
position of the second supply tube 33.
[0073] The second liquid recovery mechanism 40 of the second liquid
immersion mechanism 2 recovers the second liquid LQ2 from the
second space K2 disposed between the second optical element LS2 and
the first optical element LS1 of the projection optical system PL.
The second liquid recovery mechanism 40 includes a second liquid
recovery section 41 which is capable of recovering the second
liquid LQ2, and a second recovery tube 43 which has one end
connected to the second liquid recovery section 41. The other end
of the second recovery tube 43 is connected to the second space K2
disposed between the first optical element LS1 and the second
optical element LS2, for example, via the recovery flow passage
(44) as described later on. The second liquid recovery section 41
includes, for example, a vacuum system (suction unit) such as a
vacuum pump, and a gas/liquid separator which separates the
recovered second liquid LQ2 from the gas. It is also allowable that
all of the components including, for example, the vacuum system and
the gas/liquid separator are not provided for the exposure
apparatus EX, but to use the equipment (utility power or power
usage) of a factory or the like in which the exposure apparatus EX
is arranged, in place of at least a part or parts of the components
as described above. The operation of the second liquid recovery
mechanism 40 (second liquid recovery section 41) is controlled by
the control unit CONT. The second liquid recovery mechanism 40
recovers the second liquid LQ2, from the upper surface T2 of the
first optical element LS1, supplied from the second liquid supply
mechanism 30 in accordance with the control of the control unit
CONT.
[0074] The nozzle member 70 is held by a nozzle holder 92, and the
nozzle holder 92 is connected to the lower step 8 of the main
column 9. The main column 9, which supports the nozzle member 70
via the nozzle holder 92, is isolated via the anti-vibration unit
87 in terms of the vibration, from the barrel surface plate 5 which
supports the barrel PK of the projection optical system PL via the
flange PF. Therefore, the projection optical system PL is prevented
from any transmission of the vibration generated by the nozzle
member 70. Further, the main column 9, which supports the nozzle
member 70 via the nozzle holder 92, is isolated via the
anti-vibration unit 89 in terms of the vibration, from the
substrate surface plate 6 which supports the substrate stage PST.
Therefore, the substrate stage PST is prevented from any
transmission of the vibration generated by the nozzle member 70 via
the main column 9 and the base BP. Further, the main column 9,
which supports the nozzle member 70 via the nozzle holder 92, is
isolated via the anti-vibration unit 86 in terms of the vibration,
from the mask surface plate 4 which supports the mask stage MST.
Therefore, the mask stage MST is prevented from any transmission of
the vibration generated by the nozzle member 70 via the main column
9.
[0075] Next, the first liquid immersion mechanism 1 and the nozzle
member 70 will be explained with reference to FIGS. 2, 3, and 4.
FIG. 2 shows, with partial cutout, a schematic perspective view
illustrating those disposed in the vicinity of the nozzle member
70. FIG. 3 shows a perspective view illustrating the nozzle member
70 as viewed from a lower position. FIG. 4 shows a side sectional
view.
[0076] The nozzle member 70 is arranged in the vicinity of the end
portion on the image plane side of the projection optical system
PL. The nozzle member 70 is an annular member which is provided to
surround the circumference of the projection optical system PL over
the substrate P (substrate stage PST). In this embodiment, the
nozzle member 70 constructs a part of the first liquid immersion
mechanism 1. The nozzle member 70 has a hole 70H disposed at the
central portion thereof in which the projection optical system PL
can be arranged. As shown in FIG. 4, the first optical element LS1
and the second optical element LS2 are supported by the same barrel
(support member) PK. In this embodiment, an inner side surface 70T
of the hole 70H of the nozzle member 70 is provided opposite to a
side surface PKT of the barrel PK. A gap is provided between the
inner side surface 70T of the hole 70H of the nozzle member 70 and
the side surface PKT of the barrel PK of the projection optical
system PL. The gap is provided in order to isolate the projection
optical system PL from the nozzle member 70 in terms of the
vibration. Accordingly, the vibration, which is generated in the
nozzle member 70, is prevented from being directly transmitted to
the projection optical system PL.
[0077] The inner side surface of the hole 70H of the nozzle member
70 is lyophobic or liquid-repellent (water-repellent) with respect
to the liquid LQ. This suppresses any inflow of the liquid LQ into
the gap between the side surface of the projection optical system
PL and the inner side surface of the nozzle member 70.
[0078] Those formed on the lower surface of the nozzle member 70
include a liquid supply port 12 for supplying the first liquid LQ1,
and a liquid recovery port 22 for recovering the first liquid LQ1.
In the following description, the liquid supply port 12 of the
first liquid immersion mechanism 1 is appropriately referred to as
"first supply port 12", and the liquid recovery port 22 of the
first liquid immersion mechanism 1 is appropriately referred to as
"first recovery port 22".
[0079] Those formed in the nozzle member 70 include a first supply
flow passage 14 which is connected to the first supply port 12, and
a first recovery flow passage 24 which is connected to the first
recovery port 22. The other end of the first supply tube 13 is
connected to the first supply flow passage 14. The other end of the
first recovery tube 23 is connected to the first recovery flow
passage 24. The first supply port 12, the first supply flow passage
14, and the first supply tube 13 construct parts of the first
liquid supply mechanism 10 (first liquid immersion mechanism 1).
The first recovery port 22, the first recovery flow passage 24, and
the first recovery tube 23 construct parts of the first liquid
recovery mechanism (first liquid immersion mechanism 1).
[0080] The first supply port 12 is provided, over the substrate P
supported by the substrate stage PST, so as to oppose to the
surface of the substrate P. The first supply port 12 is separated
or away from the surface of the substrate P by a predetermined
distance. The first supply port 12 is arranged to surround the
projection area AR of the projection optical system PL onto which
the exposure light beam EL is radiated. In this embodiment, the
first supply port 12 is formed to have an annular slit-shaped
configuration at the lower surface of the nozzle member 70 to
surround the projection area AR as shown in FIG. 3. In this
embodiment, the projection area AR is set to have a rectangular
shape in which the Y axis direction (non-scanning direction) is the
longitudinal direction.
[0081] The first supply flow passage 14 is provided with a buffer
flow passage portion 14H which has a portion connected to the other
end of the first supply port 13, and an inclined flow passage
portion 14S which has an upper end connected to the buffer flow
passage portion 14H and which has a lower end connected to the
first supply port 12. The inclined flow passage portion 14S has a
shape corresponding to the first supply port 12, and its cross
section taken along the XY plane is formed to have an annular
slit-shaped configuration to surround the first optical element
LS1. The inclined flow passage portion 14S has an angle of
inclination corresponding to the side surface of the first optical
element LS1 arranged inside. As appreciated from FIG. 4, the
inclined flow passage portion 14S is formed such that the spacing
distance with respect to the surface of the substrate P is
increased at positions away farther from the optical axis AX of the
projection optical system PL as viewed in a side sectional
view.
[0082] The buffer flow passage portion 14H is a space which is
provided outside of the inclined flow passage portion 14S to
surround the upper end portion of the inclined flow passage portion
14S and which is formed to expand in the XY direction (horizontal
direction). The inner side of the buffer flow passage portion 14H
(side on the optical axis AX) is connected to the upper end of the
inclined flow passage portion 14S. The connecting section thereof
is an angular corner portion 17. A bank portion 15, which is formed
to surround the upper end of the inclined flow passage portion 14S,
is provided in the vicinity of the connecting section (angular
corner section) 17, specifically in the inner area (on the side of
the optical axis AX) of the buffer flow passage portion 14H. The
bank portion 15 is provided to protrude in the +Z direction from
the bottom surface of the buffer flow passage portion 14H. A narrow
flow passage portion 14N, which is narrower than the buffer flow
passage portion 14H, is defined between the bank portion 15 and the
upper surface (top plate portion 72B described later on) of the
nozzle member.
[0083] In this embodiment, the nozzle member 70 is formed by
combining a first member 71 and a second member 72. Each of the
first and second members 71, 72 can be formed of, for example,
aluminum, titanium, stainless steel, duralumin, or any alloy
containing at least two of them.
[0084] The first member 71 has a side plate portion 71A, a top
plate portion 71B which has its outer end connected at an upper
predetermined position of the side plate portion 71A, an inclined
plate portion 71C which has its upper end connected to an inner end
of the top plate portion 718, and a bottom plate portion 71D (see
FIG. 3) which is connected to a lower end of the inclined plate
portion 71C. The respective plate portions are joined to one
another and integrated as one body. The second member 72 has a top
plate portion 72B which has its outer end connected to an upper end
of the first member 71, an inclined plate portion 72C which has its
upper end connected to an inner end of the top plate portion 72B,
and a bottom plate portion (plate portion) 72D which is connected
to a lower end of the inclined plate portion 72C. The respective
plate portions are joined to one another and integrated as one
body. The bottom surface of the buffer flow passage portion 14H is
formed by the top plate portion 71B of the first member 71. The
ceiling surface of the buffer flow passage portion 14H is formed by
the lower surface of the top plate portion 72B of the second member
72. The bottom surface of the inclined flow passage portion 14S is
formed by the upper surface of the inclined plate portion 71C of
the first member 71 (surface directed in the direction toward the
projection optical system PL). The ceiling surface of the inclined
flow passage portion 14S is formed by the lower surface of the
inclined plate portion 72C of the second member 72 (surface
directed in the direction opposite to the projection optical system
PL). Each of the inclined plate portion 71C of the first member 71
and the inclined plate portion 72C of the second member 72 is
formed to be mortar-shaped. The slit-shaped supply flow passage 14
is formed by combining the first and second members 71, 72. The
outer portion of the buffer flow passage portion 14H is closed by
the upper area of the side plate portion 71A of the first member
71. The upper surface of the inclined plate portion 72C of the
second member 72 (i.e., the inner side surface 70T of the nozzle
member 70) is opposed to the side surface PKT of the barrel PK of
the projection optical system PL.
[0085] The first recovery port 22 is provided so that the first
recovery port 22 is opposed to the surface of the substrate P over
(above) the substrate P supported by the substrate stage PST. The
first recovery port 22 is away from the surface of the substrate P
by predetermined distances. The first recovery port 22 is provided
outside the first supply port 12 separately farther from the
projection area AR of the projection optical system PL as compared
with the first supply port 12. The first recovery port 22 is formed
to surround the first supply port 12 and the projection area AR
onto which the exposure light beam EL is radiated. Specifically, a
space 24, which is open downwardly, is formed by the side plate
portion 71A, the top plate portion 71B, and the inclined plate
portion 71C of the first member 71. The first recovery port 22 is
formed by the opening of the space 24. The first recovery flow
passage 24 is formed by the space 24. The other end of the first
recovery tube 23 is connected to a part of the first recovery flow
passage (space) 24.
[0086] A porous member or perforated member 25, which has a
plurality of pores, is arranged in the first recovery port 22 so
that the first recovery port 22 is covered therewith. The porous
member 25 is formed of a mesh member having a plurality of pores.
The porous member 25 can be constructed, for example, with a mesh
member formed with a honeycomb pattern composed of a plurality of
substantially hexagonal pores. The porous member 25 is formed to be
thin plate-shaped, which has, for example, a thickness of about 100
.mu.m.
[0087] The porous member 25 can be formed by performing a
perforating processing to a plate member which is to serve as a
base member for the porous member formed of, for example, stainless
steel (for example, SUS 316). A plurality of thin plate-shaped
porous members 25 can be laminated and arranged in the first
recovery port 22 as well. The porous member 25 may be subjected to
a surface treatment to suppress the elution of any impurity to the
first liquid LQ1 or a surface treatment to enhance the lyophilic or
liquid-attracting property. Such a surface treatment includes a
treatment in which chromium oxide is adhered to the porous member
25, including, for example, the "GOLDEP WHITE" treatment or the
"GOLDEP" treatment provided by Kobelco Eco-Solutions Co., Ltd. When
the surface treatment as described above is performed, it is
possible to avoid the inconvenience which would be otherwise
caused, for example, such that any impurity is eluted from the
porous member 25 to the first liquid LQ1. The surface treatment as
described above may be also performed to the nozzle member 70
(first and second members 71, 72). The porous member 25 may be
formed by using a material (for example, titanium) with which any
impurity is hardly eluted to the first liquid LQ1.
[0088] The nozzle member 70 has a rectangular shape as viewed in a
plan view. As shown in FIG. 3, the first recovery port 22 is formed
to be frame-shaped (having a shape of ".quadrature." (polygon)) as
viewed in a plan view to surround the projection area AR and the
first supply port 12 on the lower surface of the nozzle member 70.
The thin plate-shaped porous member 25 is arranged in the first
recovery port 22. The bottom plate portion 71D of the first member
71 is arranged between the first recovery port 22 (porous member
25) and the first supply port 12. The first supply port 12 is
formed to be annular slit-shaped as viewed in a plan view between
the bottom plate portion 71D of the first member 71 and the bottom
plate portion 72D of the second member 72.
[0089] The surfaces (lower surfaces) of the bottom plate portions
71D, 72D of the nozzle member 70, which are opposed to the
substrate P respectively, are flat surfaces which are parallel to
the XY plane. That is, the nozzle member 70 is provided with the
bottom plate portions 71D, 72D having the lower surfaces which are
formed to be opposed to the surface of the substrate P (XY plane)
supported by the substrate stage PST, and substantially in parallel
to the surface of the substrate P. In this embodiment, the lower
surface of the bottom plate portion 71D is substantially flush with
the lower surface of the bottom plate portion 72D. At this portion,
the gap is the smallest with respect to the surface of the
substrate P placed on the substrate stage PST. Accordingly, the
first liquid LQ1 can be satisfactorily retained between the
substrate P and the bottom surfaces of the bottom plate portions
71D, 72D to form the first liquid immersion area LR1. In the
following description, the lower surfaces (flat portions) of the
bottom plate portions 71D, 72D, which are formed to be opposed to
the surface of the substrate P supported by the substrate stage
PST, and substantially in parallel to the surface of the substrate
P (XY plane), are appropriately referred to as "land surface 75" in
combination.
[0090] The land surface 75 is the surface which is included in the
nozzle member 70 and which is arranged at the position nearest to
the substrate P supported by the substrate stage PST. In this
embodiment, the lower surface of the bottom plate portion 71D and
the lower surface of the bottom plate portion 72D are collectively
designated as the land surface 75, because the lower surface of the
bottom plate portion 71D is substantially flush with the lower
surface of the bottom plate portion 72D. However, the porous member
25 may be also arranged on the lower surface of the bottom plate
portion 71D to provide a part of the first recovery port 22. In
this arrangement, only the lower surface of the bottom plate
portion 72D is the land surface 75.
[0091] The porous member 25 has a lower surface 26 which is opposed
to the substrate P supported by the substrate stage PST. The porous
member 25 is provided in the first recovery port 22 so that the
lower surface 26 is inclined with respect to the surface of the
substrate P supported by the substrate stage PST (i.e., the XY
plane). That is, the porous member 25, which is provided in the
first recovery port 22, has the inclined surface (lower surface) 26
which is opposed to the surface of the substrate P supported by the
substrate stage PST. The first liquid LQ1 is recovered via the
inclined surface 26 of the porous member 25 arranged in the first
recovery port 22. That is, in this arrangement, the first recovery
port 22 is formed on the inclined surface 26. The first recovery
port 22 is formed to surround the projection area AR onto which the
exposure light beam EL is radiated. Therefore, in this arrangement,
the inclined surface 26 of the porous member 25 arranged in the
first recovery port 22 is formed to surround the projection area AR
onto which the exposure light beam EL is radiated.
[0092] The inclined surface 26 of the porous member 25 opposed to
the substrate P is formed such that the spacing distance with
respect to the surface of the substrate P is increased at positions
separated farther from the optical axis AX of the projection
optical system PL (exposure light beam EL). As shown in FIG. 3, the
first recovery port 22 is formed to have a shape of ".quadrature."
(polygon) as viewed in a plan view in this embodiment. Four porous
members 25A to 25D are combined and arranged in the first recovery
port 22. In particular, the porous members 25A, 250, which are
arranged on the both sides in the X axis direction (scanning
direction) with respect to the projection area AR respectively, are
arranged so that the spacing distances with respect to the surface
of the substrate P are increased at positions separated farther
from the optical axis AX, with the surfaces thereof crossing at
right angles with respect to the XZ plane. The porous members 25B,
25D, which are arranged on the both sides in the Y axis direction
with respect to the projection area AR respectively, are arranged
so that the spacing distances with respect to the surface of the
substrate P are increased at positions separated farther from the
optical axis AX, with the surfaces thereof crossing at right angles
with respect to the YZ plane.
[0093] The lower surface of the bottom plate portion 71D connected
to the lower end of the inclined plate portion 71C of the first
member 71 and the lower end of the side plate portion 71A are
provided to have approximately the same position (height) in the Z
axis direction. The porous member 25 is attached to the first
recovery port 22 of the nozzle member 70 so that the inner edge of
the inclined surface 26 has approximately the same height as that
of the lower surface (land surface 75) of the bottom plate portion
71D, and the inner edge of the inclined surface 26 is continuous to
the lower surface (land surface 75) of the bottom plate portion
71D. That is, the land surface 75 is formed continuously to the
inclined surface 26 of the porous member 25. The porous member 25
is arranged so that the spacing distances are increased with
respect to the surface of the substrate P at positions separated
farther from the optical axis AX. A wall portion 76, which is
formed by a partial area of the lower portion of the side plate
portion 71A, is provided outside the outer edge of the inclined
surface 26 (porous member 25). The wall portion 76 is provided at
the circumferential edge of the porous member 25 (inclined surface
26) to surround the porous member 25. The wall portion 76 is
provided outside the first recovery port 22 with respect to the
projection area AR in order to suppress the leakage of the first
liquid LQ1.
[0094] A part of the bottom plate portion 72D for forming the land
surface 75 is arranged between the substrate P and the lower
surface T1 of the first optical element LS1 of the projection
optical system PL in relation to the Z axis direction. That is, a
part of the bottom plate portion 72D for forming the land surface
75 is provided under the lower surface T1 of the optical element
LS1 of the projection optical system PL. An opening 74, through
which the exposure light beam EL passes, is formed at a central
portion of the bottom plate portion 72D which forms the land
surface 75. The opening 74 has a shape corresponding to the
projection area AR. In this embodiment, the opening 74 is formed to
have an elliptical shape in which the Y axis direction
(non-scanning direction) is the longitudinal direction. The opening
74 is formed to be larger or greater than the projection area AR.
The exposure light beam EL, which has passed through the projection
optical system PL, can arrive at the surface of the substrate P
without being blocked or shielded by the bottom plate portion 72D.
That is, the bottom plate portion 72D, which forms the land surface
75, is arranged so that the bottom plate portion 72D is provided
under the lower surface T1 of the first optical element LS1 to
surround the optical path for the exposure light beam EL at the
position at which the optical path for the exposure light beam EL
is not disturbed. In other words, the land surface 75 is arranged
to surround the projection area AR between the substrate P and the
lower surface T1 of the first optical element LS1. The bottom plate
portion 72D is arranged opposite to the surface of the substrate P
with the lower surface thereof being the land surface 75. The
bottom plate portion 72D is provided to make no contact with the
substrate P and the lower surface T1 of the first optical element
LS1. An edge portion 74E of the opening 74 may be formed to be
right-angled, acute-angled, or circular arc-shaped.
[0095] In this arrangement, the land surface 75 is arranged between
the projection area AR onto which the exposure light beam EL is
radiated and the inclined surface 26 of the porous member 25 which
is arranged in the first recovery port 22. In this arrangement, the
first recovery port 22 is arranged to surround the land surface 75
in the outside of the land surface 75 with respect to the
projection area AR. In this arrangement, the first supply port 12
is arranged outside the land surface 75 (bottom plate portion 72D)
with respect to the projection area AR. In this arrangement, the
first supply port 12 is provided between the first recovery port 22
and the projection area AR of the projection optical system PL. The
first liquid LQ1 for forming the first liquid immersion area LR1 is
supplied, via the first supply port 12, between the first recovery
port 22 and the projection area AR of the projection optical system
PL.
[0096] This embodiment adopts such an arrangement that the first
recovery port 22 is formed to have a shape of ".quadrature."
(polygon) to surround the land surface 75. However, the first
recovery port 22 may be arranged such that the first recovery port
22 does not surround the land surface 75, provided that the first
recovery port 22 is disposed outside the land surface 75 with
respect to the projection area AR. For example, the first recovery
port 22 may be arranged in a divided manner in predetermined areas,
of the lower surface of the nozzle member 70, which are disposed
outside the land surface 75 on the both sides in the scanning
direction (X axis direction) with respect to the projection area
AR. Alternatively, the first recovery port 22 may be arranged in a
divided manner in predetermined areas, of the lower surface of the
nozzle member 70, which are disposed outside the land surface 75 on
the both sides in the non-scanning direction (Y axis direction)
with respect to the projection area AR. On the other hand, when the
first recovery port 22 is arranged to surround the land surface 75,
it is possible to recover the first liquid LQ1 via the first
recovery port 22 more reliably.
[0097] As described above, the land surface 75 is arranged between
the substrate P and the lower surface T1 of the first optical
element LS1. The distance between the surface of the substrate P
and the lower surface T1 of the first optical element LS1 is longer
than the distance between the land surface 75 and the surface of
the substrate P. That is, the lower surface T1 of the first optical
element LS1 is formed at the position higher than that of the land
surface 75 (to be far from the substrate P).
[0098] At least a part of the first recovery port 22 including the
inclined surface 26 formed continuously to the land surface 75 is
arranged opposite to the surface of the substrate P between the
substrate P and the lower surface T1 of the first optical element
LS1 in relation to the Z axis direction. That is, at least a part
of the first recovery port 22 is provided at the position lower
than that of the lower surface T1 of the first optical element LS1
(to be near to the substrate P). In this arrangement, the first
recovery port 22 including the inclined surface 26 is arranged
around the lower surface T1 of the first optical element LS1.
[0099] In this embodiment, the distance between the lower surface
T1 of the first optical element LS1 and the upper surface T2 of the
first optical element LS1 is about 4 mm. The distance between the
substrate P and the lower surface T1 of the first optical element
LS1, i.e., the thickness of the liquid LQ1 in the optical path for
the exposure light beam EL is about 3 mm. The distance between the
land surface 75 and the substrate P is about 1 mm. The first liquid
LQ1 of the first liquid immersion area LR1 makes contact with the
land surface 75. The first liquid LQ1 of the first liquid immersion
area LR1 also makes contact with the lower surface T1 of the first
optical element LS1. That is, the land surface 75 and the lower
surface T1 of the first optical element LS1 serve as the liquid
contact surfaces to make contact with the first liquid LQ1 of the
first liquid immersion area LR1.
[0100] The distance between the lower surface T1 of the first
optical element LS1 and the upper surface T2 of the first optical
element LS1 is not limited to 4 mm as described above, and can be
set within a range of 3 to 10 mm. The distance between the
substrate P and the lower surface T1 of the first optical element
LS1 is not limited to 3 mm as described above, and can be set
within a range of 1 to 5 mm, considering the absorption of the
exposure light beam EL by the liquid LQ1 and the flow of the liquid
LQ1 in the first space K1. Further, the distance between the land
surface 75 and the substrate P is not limited to 1 mm as described
above as well, and can be set within a range of 0.5 to 1 mm.
[0101] The lower surface (liquid contact surface) T1 of the first
optical element LS1 of the projection optical system PL has the
liquid-attracting (hydrophilic) property. In this embodiment, the
liquid-attracting treatment is performed to the lower surface T1.
The lower surface T1 of the first optical element LS1 is
liquid-attractive by the aid of the liquid-attracting treatment.
The liquid-attracting treatment is also performed to the land
surface 75 to have the liquid-attracting property. The
liquid-repelling treatment may be performed to a part of the land
surface 75 to have the liquid-repelling property.
[0102] The liquid-attracting treatment, which is applied in order
to make a predetermined member such as the lower surface T1 of the
first optical element LS1 to be liquid-attractive, includes, for
example, a treatment for adhering a liquid-attracting material such
as MgF.sub.2, Al.sub.2O.sub.3, and SiO.sub.2. Alternatively, as for
the liquid-attracting treatment (water-attracting treatment), the
liquid-attracting property (hydrophilic property) can be also
performed, for example, by forming a thin film with a substance
such as alcohol having a molecular structure with large polarity
provided with the OH group, because the liquid LQ is water having
large polarity in this embodiment. Further, when the first optical
element LS1 is formed of calcium fluorite or silica glass, it is
possible to obtain the satisfactory liquid-attracting property even
when no liquid-attracting treatment is performed, because calcium
fluorite or silica glass has the high affinity for water. It is
possible to allow the first liquid LQ1 to make tight contact with
the substantially entire surface of the lower surface T1 of the
first optical element LS1. A part of the land surface 75 (for
example, the lower surface of the bottom plate portion 71D) may be
liquid-repellent with respect to the first liquid LQ1.
[0103] The liquid-repelling treatment, which is adopted in order to
make a part of the land surface 75 to be liquid-repellent,
includes, for example, a treatment to adhere a liquid-repelling
material including, for example, fluorine-based materials such as
polytetrafluoroethylene (Teflon (trade name)), acrylic resin
materials, and silicon-based resin materials. When the upper
surface 91 of the substrate stage PST is made to be
liquid-repellent, then it is possible to suppress the outflow of
the first liquid LQ1 to the outside of the substrate P (outside of
the upper surface 91) during the liquid immersion exposure, it is
possible to smoothly recover the liquid LQ1 after the liquid
immersion exposure as well, and it is possible to avoid the
inconvenience which would be otherwise caused such that the first
liquid LQ1 remains on the upper surface 91.
[0104] In order to supply the first liquid LQ1 onto the substrate
P, the control unit CONT drives the first liquid supply section 11
to feed the first liquid LQ1 from the first liquid supply section
11. The first liquid LQ1, which is fed from the first liquid supply
section 11, flows through the first supply tube 13, and then the
first liquid LQ1 flows into the buffer flow passage portion 14H of
the first supply flow passage 14 of the nozzle member 70. The
buffer flow passage portion 14H is the space which is expanded in
the horizontal direction. The first liquid LQ1, which has flown
into the buffer flow passage portion 14H, flows to expand in the
horizontal direction. The bank portion 15 is formed in the inner
area (on the side of the optical axis AX) as the downstream side of
the flow passage of the buffer flow passage portion 14H. Therefore,
the first liquid LQ1 is expanded over the entire region of the
buffer flow passage portion 14H, and then the first liquid LQ1 is
once pooled. After the first liquid LQ1 is pooled in an amount not
less than a predetermined amount in the buffer flow passage portion
14H (after the liquid level of the first liquid LQ1 is not less
than the height of the bank portion 15), the first liquid LQ1 flow
into the inclined flow passage portion 14S via the narrow flow
passage portion 14N. The first liquid LQ1, which has flown into the
inclined flow passage portion 14S, flows downwardly along the
inclined flow passage portion 14S. The first liquid LQ1 is supplied
from the first supply port 12 onto the substrate P arranged on the
image plane side of the projection optical system PL. The first
supply port 12 supplies the first liquid LQ1 onto the substrate P
from the position over the substrate P.
[0105] Owing to the provision of the bank portion 15 as described
above, the first liquid LQ1, which has flown out from the buffer
flow passage portion 14H, is supplied onto the substrate P
substantially uniformly from the entire region of the first supply
port 12 formed annularly to surround the projection area AR. That
is, if the bank portion 15 (narrow flow passage portion 14N) is not
formed, the flow rate of the first liquid LQ1 allowed to flow
through the inclined flow passage portion 14S is greater in the
area disposed in the vicinity of the connecting section between the
first supply tube 13 and the buffer flow passage portion 14H than
in the other areas. Therefore, the liquid supply amount for the
surface of the substrate P is sometimes nonuniform at respective
positions of the first supply port 12 which is formed annularly.
However, the buffer flow passage portion 14H is formed to be
provided with the narrow flow passage portion 14N, and the liquid
supply to the first supply port 12 is started after the first
liquid LQ1 of the amount not less than the predetermined amount is
pooled in the buffer flow passage portion 14H. Therefore, the first
liquid LQ1 can be supplied onto the substrate P in the state in
which the flow rate distribution and the flow velocity distribution
are uniformized at the respective positions of the first supply
port 12. Any bubble tends to remain, for example, upon the start of
the supply in the vicinity of the angular corner portion 17 of the
first supply flow passage 14. However, the narrow flow passage
portion 14N is formed by narrowing the first supply flow passage 14
in the vicinity of the angular corner portion 17. Accordingly, the
high velocity is obtained for the flow rate of the first liquid LQ1
flowing through the narrow flow passage portion 14N. The bubble can
be discharged to the outside of the first supply flow passage 14
via the first supply port 12 in accordance with the flow of the
first liquid LQ1 having the high velocity. When the liquid
immersion exposure operation is executed after discharging the
bubble, the exposure process can be performed in the state in which
any bubble is absent in the first liquid immersion area LR1. The
bank portion 15 may be provided to protrude in the -Z direction
from the ceiling surface of the buffer flow passage portion 14H. In
principle, it is enough that the narrow flow passage portion 14N,
which is narrower than the buffer flow passage portion 14H, is
provided on the downstream side of the flow passage as compared
with the buffer flow passage portion 14H.
[0106] The height of the bank portion 15 may be partially lowered
(raised). When the bank portion 15 is provided with the area which
partially has any different height, the supply of the first liquid
LQ1 from the first supply port 12 can be started at any partially
different timing. Therefore, it is possible to avoid the remaining
of the gas (bubble) in the liquid for forming the liquid immersion
area AR2 when the supply of first liquid LQ1 is started.
Alternatively, the buffer flow passage portion 14H may be divided
into a plurality of flow passages to successfully supply the liquid
LQ in different amounts depending on the positions of the
slit-shaped liquid supply port 12.
[0107] In order to recover the liquid LQ1 from the surface of the
substrate P, the control unit CONT drives the first liquid recovery
section 21. When the first liquid recovery section 21, which has
the vacuum system, is driven, the liquid LQ1, which is disposed on
the substrate P, is allowed to flow into the first recovery flow
passage 24 via the first recovery port 22 arranged with the porous
member 25. When the first liquid LQ1 in the first liquid immersion
area LR1 is recovered, the lower surface (inclined surface) 26 of
the porous member 25 makes contact with the first liquid LQ1. The
first recovery port 22 (porous member 25) is provided over (above)
the substrate P to oppose to the substrate P. Therefore, the first
recovery port 22 (porous member 25) recovers the first liquid LQ1
from the surface of the substrate P from the position thereover.
The first liquid LQ1, which has flown into the first recovery flow
passage 24, flows through the first recovery tube 23, and then the
first liquid LQ1 is recovered by the first liquid recovery section
21.
[0108] Next, the second liquid immersion mechanism 2 will be
explained with reference to FIGS. 4, 5, 6, and 7.
[0109] With reference to FIG. 4, the first optical element LS1 and
the second optical element LS2 are supported by the same barrel
(support member) PK, and they are supported in the substantially
stationary state with respect to the optical path for the exposure
light beam EL. The first optical element LS1 is supported by a
first support section 91 which is provided at the lower end of the
barrel PK. The second optical element LS2 is supported by a second
support section 92 which is provided over (above) the first support
section 91 in the barrel PK. A flange portion F2, which serves as a
support objective portion, is provided at an upper portion of the
second optical element LS2. The second support section 92 supports
the second optical element LS2 by supporting the flange portion F2.
The first optical element LS1 is easily attachable/detachable with
respect to the first support section 91 of the barrel PK. That is,
the first optical element LS1 is provided exchangeably. It is also
allowable that the first support section 91, which supports the
first optical element LS1, may be attachable/detachable with
respect to the second support section 92, and the first support
section 91 and the first optical element LS1 may be exchanged
together.
[0110] The first optical element LS1 is a parallel flat plate, in
which the lower surface T1 and the upper surface T2 are in parallel
to one another. The lower surface T1 and the upper surface T2 are
substantially in parallel to the XY plane. The surface of the
substrate P supported by the substrate stage PST is substantially
in parallel to the XY plane. Therefore, the lower surface T1 and
the upper surface T2 are substantially in parallel to the surface
of the substrate P supported by the substrate stage PST. The lower
surface T1 of the first optical element LS1 supported by the first
support section 91 is substantially flush with the lower surface
PKA of the barrel PK. The bottom plate portion 72D, which forms the
land surface 75, extends under the lower surface T1 of the first
optical element LS1 and the lower surface PKA of the barrel PK.
[0111] The lower surface T3 of the second optical element LS2 is
formed to be flat surface-shaped. The lower surface T3 of the
second optical element LS2 supported by the second support section
92 is substantially in parallel to the upper surface T2 of the
first optical element LS1 supported by the first support section
91. On the other hand, the upper surface T4 of the second optical
element LS2 is formed to be convex toward the object plane (toward
the mask M), and has a positive refractive power. Accordingly, the
reflection loss of the light beam (exposure light beam EL) allowed
to come into the upper surface T4 is reduced. Consequently, the
large image side numerical aperture of the projection optical
system PL is secured. The second optical element LS2, which has the
refractive power (lens function), is supported by the second
support section 92 of the barrel PK in the state of being
positioned satisfactorily.
[0112] In this embodiment, the outer diameter D3 of the lower
surface T3 of the second optical element LS2 opposed to the first
optical element LS1 is formed to be smaller than the outer diameter
D2 of the upper surface T2 of the first optical element LS1.
[0113] As described above, the exposure light beam EL passes
through the respective predetermined areas of the upper surface T4
and the lower surface T3 of the second optical element LS2.
Further, the exposure light beam EL passes through the respective
predetermined areas of the upper surface T2 and the lower surface
T1 of the first optical element LS1.
[0114] For example, the connecting portion between the barrel PK
and the first optical element LS1 is sealed. That is, the first
space K1 disposed on the side of the lower surface T1 of the first
optical element LS1 and the second space K2 disposed on the side of
the upper surface T2 of the first optical element LS1 are the
spaces which are independent from each other. The flow of the
liquid is prohibited between the first space K1 and the second
space K2. As described above, the first space K1 is the space
between the first optical element LS1 and the substrate P. The
first liquid immersion area LR1 of the first liquid LQ1 is formed
in the first space K1. On the other hand, the second space K2 is a
part of the internal space of the barrel PK. The second space K2 is
the space disposed between the upper surface T2 of the first
optical element LS1 and the lower surface T3 of the second optical
element LS2 arranged thereover. The second liquid immersion area
LR2 of the second liquid LQ2 is formed in the second space K2. A
gap is provided between the side surface C2 of the second optical
element LS2 and the inner side surface PKC of the barrel PK.
[0115] As shown in FIG. 4, the other end of a second supply tube 33
is connected to one end of a second supply flow passage 34 formed
in the barrel PK. On the other hand, the other end of the second
supply flow passage 34 of the barrel PK is connected to a supply
member 35 arranged inside (in the internal space of) the barrel PK.
The supply member 35, which is arranged inside the barrel PK, has a
liquid supply port 32 for supplying the second liquid LQ2 to the
second space K2. A supply flow passage 36, through which the second
liquid LQ2 flows, is formed in the supply member 35. The connecting
portion of the second supply flow passage 34 with respect to the
supply member 35 (supply flow passage 36) is provided in the
vicinity of the second space K2 on the inner side surface PKC of
the barrel PK.
[0116] The other end of the second recovery tube 43 is connected to
one end of a second recovery flow passage 44 formed in the barrel
PK. On the other hand, the other end of the second recovery flow
passage 44 of the barrel PK is connected to a recovery member 45
arranged inside (in the internal space of) the barrel PK. The
recovery member 45, which is arranged inside the barrel PK, has
liquid recovery ports 42 for recovering the second liquid LQ2 from
the second space K2. A recovery flow passage 46, through which the
second liquid LQ2 flows, is formed in the recovery member 45. The
connecting portion of the second recovery flow passage 44 with
respect to the recovery member 45 (recovery flow passage 46) is
provided in the vicinity of the second space K2 on the inner side
surface PKC of the barrel PK.
[0117] The liquid supply port 32, the supply member 35 (supply flow
passage 36), the second supply flow passage 34, and the second
supply tube 33 construct a part of the second liquid supply
mechanism 30 (second liquid immersion mechanism 2). The liquid
recovery ports 42, the recovery member 45 (recovery flow passage
46), the second recovery flow passage 44, and the second recovery
tube 43 construct a part of the second liquid recovery mechanism 40
(second liquid immersion mechanism 2). In the following
description, the liquid supply port 32 of the second liquid
immersion mechanism 2 is appropriately referred to as "second
supply port 32", and the liquid recovery port 42 of the second
liquid immersion mechanism 2 is appropriately referred to as
"second recovery port 42".
[0118] FIG. 5 illustrates the second liquid immersion mechanism 2
for forming the second liquid immersion area LR2, wherein FIG. 5(a)
shows a side view, and FIG. 5(b) shows a view taken along a line
A-A shown in FIG. 5(a). As shown in FIG. 5, the supply member 35 is
constructed of a shaft-shaped member extending in the horizontal
direction. In this embodiment, the supply member 35 is arranged on
the +X side of the predetermined area AR' of the upper surface T2
of the first optical element LS1 through which exposure light beam
EL passes. The supply member 35 is provided to extend in the X axis
direction. One end of the supply flow passage 36 formed in the
supply member 35 is connected to the other end of the second supply
flow passage 34 (see FIG. 4) formed in the barrel PK. The other end
of the supply flow passage 36 is connected to the second supply
port 32. The second supply port 32 is formed so that the second
supply port 32 is directed toward the -X side. The second supply
port 32 discharges the second liquid LQ2 substantially in parallel
to the upper surface T2 of the first optical element LS1, i.e.,
substantially in parallel to the XY plane (in the lateral
direction). The second supply port 32 of the second liquid
immersion mechanism 2 is arranged in the second space K2.
Therefore, the second liquid supply section 31 is connected to the
second space K2, for example, via the second supply tube 33, the
second supply flow passage 34, and the second supply port 32.
[0119] Gaps are provided between the supply member 35 and the upper
surface T2 of the first optical element LS1 and between the supply
member 35 and the lower surface T3 of the second optical element
LS2 respectively. That is, the supply member 35 is supported by the
barrel PK or a predetermined support mechanism so that the supply
member 35 is in a non-contact state with respect to the first
optical element LS1 and the second optical element LS2
respectively. Accordingly, the vibration, which is generated in the
supply member 35, is prevented from being directly transmitted to
the first and second optical elements LS1, LS2. When the supply
member 35 is allowed to be in the non-contact state with respect to
the first optical element LS1 and the second optical element LS2
respectively, it is possible to suppress the change of the shape of
each of the first optical element LS1 and the second optical
element LS2. Thus, it is possible to maintain the high image
formation performance of the projection optical system PL.
[0120] The supply member 35 is provided at the position at which
the radiation of the exposure light beam EL is not disturbed, i.e.,
outside the predetermined area AR' of the upper surface T2 of the
first optical element LS1 through which the exposure light beam EL
passes. The second supply port 32 is arranged at the predetermined
position between the predetermined area AR' and the edge portion of
the upper surface T2 of the first optical element LS1 in the second
space K2.
[0121] When the control unit CONT is operated to feed the second
liquid LQ2 from the second liquid supply section 31 of the second
liquid supply mechanism 30 in order to form the second liquid
immersion area LR2, then the second liquid LQ2, which is fed from
the second liquid supply section 31, flows through the second
supply tube 33, and then the second liquid LQ2 flows into one end
of the second supply flow passage 34 formed in the barrel PK. The
liquid LQ2, which has flown into one end of the second supply flow
passage 34, flows through the second supply flow passage 34, and
then the liquid LQ2 flows into one end of the supply flow passage
36 of the supply member 35 connected to the other end thereof. The
second liquid LQ2, which has flown into one end of the supply flow
passage 36, flows through the supply flow passage 36, and then the
second liquid LQ2 is supplied to the second space K2 via the second
supply port 32. The second liquid LQ2, which has been supplied from
the second supply port 32, locally forms the second liquid
immersion area LR2 in only a partial area of the upper surface T2
of the first optical element LS1, the partial area being smaller
than the upper surface T2 and the partial area being greater than
the predetermined area AR' through which the exposure light beam EL
passes. The second liquid LQ2, which has been supplied to the space
between the first optical element LS1 and the second optical
element LS2, is retained by the surface tension between the upper
surface T2 of the first optical element LS1 and the lower surface
T3 of the second optical element LS2. The second liquid LQ2 in the
second liquid immersion area LR2 makes contact with the partial
area of the upper surface T2 of the first optical element LS1, and
the second liquid LQ2 makes contact with the substantially entire
surface of the lower surface T3 of the second optical element LS2.
As described above, the outer diameter D3 of the lower surface T3
of the second optical element LS2 is smaller than the outer
diameter D2 of the upper surface T2 of the first optical element
LS1. Therefore, the second liquid LQ2, with which the space between
the first optical element LS1 and the second optical element LS2 is
filled, can form the second liquid immersion area LR2 which is
smaller than the upper surface T2 of the first optical element LS1,
below the lower surface T3 of the second optical element LS2 (above
the upper surface T2 of the first optical element LS1).
[0122] In this embodiment, the distance between the upper surface
T2 of the first optical element LS1 and the lower surface T3 of the
second optical element LS2, i.e., the thickness of the liquid LQ2
in the optical path for the exposure light beam EL is about 3 mm.
However, the distance between the upper surface T2 of the first
optical element LS1 and the lower surface T3 of the second optical
element LS2 is not limited to 3 mm as described above, and can be
set within a range of 0.5 to 5 mm considering the absorption of the
exposure light beam EL by the liquid LQ2 and the flow of the liquid
LQ2 in the second space K2.
[0123] As shown in FIG. 6, the surface of the first area HR1, which
is the partial area to serve as the second liquid immersion area
LR2 and which is included in the upper surface T2 of the first
optical element LS1 facing the second space K2, has the affinity
for the second liquid LQ2, the affinity being higher than the
affinity for the second liquid LQ2 of the surface of the second
area HR2 as the area around the first area HR1. That is, the
contact angle of the surface of the first area HR1 with respect to
the second liquid LQ2 is smaller than the contact angle of the
surface of the second area HR2 with respect to the second liquid
LQ2. Specifically, the surface of the second area HR2 is
liquid-repellent with respect to the second liquid LQ2.
Accordingly, when the second liquid immersion area LR2 of the
second liquid LQ2 is formed in the partial area (first area HR1) of
the upper surface T2 of the first optical element LS1, it is
possible to avoid the inconvenience which would be otherwise caused
such that the second liquid LQ2 outflows to the outside of the
upper surface T2. The first area HR1 includes the predetermined
area AR' through which the exposure light beam EZ passes. When the
surface of the first area HR1 including the predetermined area AR'
is liquid-attractive, the second liquid LQ2 can be allowed to make
tight contact with the surface of the first area HR1
satisfactorily.
[0124] In this embodiment, the liquid-repelling property is applied
to the surface of the second area HR2 by performing the
liquid-repelling treatment to the surface of the second area HR2.
The liquid-repelling treatment, which is adopted in order to allow
the surface of the second area HR2 to be liquid-repellent,
includes, for example, a treatment to coat a liquid-repelling
material including, for example, fluorine-based materials such as
polytetrafluoroethylene, acrylic resin materials, and silicon-based
resin materials, and a treatment to stuck a thin film formed of the
liquid-repelling material as described above. In this embodiment,
the surface of the second area HR2 is coated with "CYTOP" produced
by Asahi Glass Co., Ltd.
[0125] In this embodiment, at least the first and second optical
elements LS1, LS2, which make contact with the first and second
liquids LQ1, LQ2 and which are included in the plurality of optical
elements LS1 to LS7, are formed of silica glass. Silica glass has
the high affinity for the first and second liquids LQ1, LQ2 as
water. Accordingly, it is possible to allow the first and second
liquids LQ1, LQ2 to make tight contact with the substantially
entire regions of the first area HR1 of the upper surface T2 and
the lower surface T1 as the liquid contact surfaces of the first
optical element LS1 and the lower surface T3 as the liquid contact
surface of the second optical element LS2. Therefore, it is
possible to allow the first and second liquids LQ1, LQ2 to make
tight contact with the liquid contact surfaces of the first and
second optical elements LS1, LS2 to reliably fill the optical path
between the second optical element LS2 and the first optical
element LS1 with the second liquid LQ2 and reliably fill the
optical path between the first optical element LS1 and the
substrate P with the first liquid LQ1.
[0126] Silica glass is a material having the large refractive
index. Therefore, for example, the size of the second optical
element LS2 can be decreased. It is possible to realize compact
sizes of the entire projection optical system PL and the entire
exposure apparatus EX. Further, silica glass is water-resistant.
Therefore, an advantage is obtained, for example, such that it is
unnecessary to provide any protective film for the liquid contact
surface.
[0127] At least one of the first and second optical elements LS1,
LS2 may be calcium fluorite having the high affinity for water. For
example, the optical elements LS3 to LS7 may be formed of calcium
fluorite, and the optical elements LS1, LS2 may be formed of silica
glass. All of the optical elements LS1 to LS7 may be formed of
silica glass (or calcium fluorite).
[0128] The water-attracting (liquid-attracting) treatment, in which
a liquid-attracting material such as MgF.sub.2, Al.sub.2O.sub.3,
and SiO.sub.2 is adhered, may be performed to the liquid contact
surfaces of the first and second optical elements LS1, LS2
including the first area HR1 of the upper surface T2 of the first
optical element LS1 to further enhance the affinity for the first
and second liquids LQ1, LQ2. Alternatively, as for the
liquid-attracting treatment (water-attracting treatment), the
hydrophilic property can be also applied to the liquid contact
surfaces of the optical elements LS1, LS2, for example, by forming
a thin film with a substance such as alcohol having a molecular
structure with large polarity, because the first and second liquids
LQ1, LQ2 are water having large polarity in this embodiment.
[0129] In this arrangement, the second area HR2, which is disposed
around the first area HR1 including the predetermined area AR' of
the upper surface T2 of the first optical element LS1 through which
the exposure light beam EL passes, is liquid-repellent. However, it
is also allowable that an area, which is disposed around a partial
area including a predetermined area of the lower surface T3 of the
second optical element LS2 through which the exposure light beam EL
passes, may be liquid-repellent.
[0130] With reference to FIG. 5(b) again, the recovery member 45
includes a shaft portion 45A, and an annular portion 45B which is
connected to the shaft portion 45A. The shaft portion 45A is
provided to extend in the horizontal direction. In this embodiment,
the shaft portion 45A is arranged on the -X side in relation to the
predetermined area AR', and the shaft portion 45A is provided to
extend in the X axis direction. The annular portion 45E is formed
to be smaller than the edge portion of the upper surface T2 of the
first optical element LS1, and a part of the annular portion 45B on
the -X side is connected to the shaft portion 45A. On the other
hand, a part of the annular portion 45E on the +X side is open or
discontinuous, and the supply member 35 is arranged at an opening
45K.
[0131] The recovery flow passage 46, which corresponds to the shape
of the recovery member 45, is formed in the recovery member 45. One
end of the recovery flow passage 46, which is formed in the shaft
portion 45A of the recovery member 45, is connected to the other
end of the second recovery flow passage 44 (see FIG. 4) formed in
the barrel PK. The annular recovery flow passage 46 is formed in
the annular portion 45B of the recovery member 45 to surround the
predetermined area AR'. The other end of the recovery flow passage
46 formed in the shaft portion 45A is connected to a part of the
annular recovery flow passage 46 formed in the annular portion
45B.
[0132] The second recovery ports 42 are formed on the inner side
surface of the annular portion 45B directed to the predetermined
area AR'. The second recovery ports 42 are provided to recover the
second liquid LQ2 from the second space K2. The plurality of second
recovery ports 42 are provided on the inner side surface of the
annular portion 45B to surround the second liquid immersion area
LR2 formed on the upper surface T2 of the first optical element
LS1. The plurality of second recovery ports 42, which are provided
on the inner side surface of the annular portion 45B, are connected
to the recovery flow passage 46 formed in the annular portion 45B.
The second recovery ports 42 of the second liquid immersion
mechanism 2 are arranged in the second space K2. Therefore, in this
arrangement, the second liquid recovery section 41 is connected to
the second space K2, via the second recovery tube 43, the second
recovery flow passage 44, and the second recovery ports 42 or the
like.
[0133] The recovery member 45 (annular portion 45B) is provided
outside the predetermined area AR' at the position at which the
radiation of the exposure light beam EL is not disturbed, i.e., at
the position to surround the predetermined area AR' of the upper
surface T2 of the first optical element LS1 through which the
exposure light beam EL passes. The second recovery ports 42 are
arranged at the predetermined positions between the predetermined
area AR' and the edge portion of the upper surface T2 in the second
space K2.
[0134] Gaps are provided between the recovery member 45 and the
upper surface T2 of the first optical element LS1 and between the
recovery member 45 and the lower surface T3 of the second optical
element LS2 respectively. That is, the recovery member 45 is
supported by the barrel PK or a predetermined support mechanism so
that the recovery member 45 is in the non-contact state with
respect to the first optical element LS1 and the second optical
element LS2 respectively. Accordingly, the vibration, which is
generated in the recovery member 45, is prevented from being
directly transmitted to the first and second optical elements LS1,
LS2.
[0135] When the second liquid LQ2 of the second liquid immersion
area LR2 is recovered, the control unit CONT drives the second
liquid recovery section 41 of the second liquid recovery mechanism
40. When the second liquid recovery section 41 having the vacuum
system is driven, the second liquid LQ2 of the second liquid
immersion area LR2 flows into the recovery flow passage 46 formed
in the annular portion 45B of the recovery member 45 via the second
recovery ports 42. The second recovery ports 42 are arranged to
surround the second liquid immersion area LR2. Therefore, the
second liquid LQ2 of the second liquid immersion area LR2 is
recovered from the surrounding thereof via the second recovery
ports 42. It is desirable that a porous member is also arranged for
the second recovery ports 42 to suppress the vibration generated
when the second liquid LQ2 is recovered.
[0136] As shown in FIG. 6, a protruding area HRT, which protrudes
inwardly (toward the predetermined area AR'), is provided for the
second area HR2 having the liquid-repelling property of the upper
surface T2 of the first optical element LS1. In this embodiment,
the protruding area HRT is provided at the position corresponding
to the opening 45K of the annular portion 45B of the recovery
member 45. Accordingly, when the second liquid LQ2 is recovered via
the second recovery ports 42 from the surrounding of the second
liquid immersion area LR2 in a state in which the supply of the
second liquid LQ2 from the second supply port 32 is stopped, the
second liquid LQ2 of the second liquid immersion area LR2 is
recovered via the second recovery ports 42 arranged around the
second liquid immersion area LR2 so that the second liquid LQ2 is
divided at the protruding area HRT as a base point, as
schematically shown in FIG. 7. In this way, it is possible to avoid
the inconvenience which would be otherwise caused, for example,
such that the second liquid LQ2 is unsuccessfully recovered and the
second liquid LQ2 remains, for example, at a central portion of the
first area HR1. Therefore, it is possible to avoid the occurrence
of the inconvenience resulting from the remaining second liquid
LQ2, which would be otherwise caused, for example, such that the
remaining second liquid LQ2 is vaporized, and any adhesion trace
(so-called water mark) is formed on the upper surface T2.
[0137] In this embodiment, the protruding area HRT is provided at
the position corresponding to the opening 45K of the annular
portion 45B of the recovery member 45. However, the protruding area
HRT may be provided at any position other than the position
corresponding to the opening 45K. The protruding area HRT shown in
the drawing is substantially rectangular as viewed in a plan view.
However, it is possible to adopt any arbitrary shape including, for
example, triangular and semicircular shapes.
[0138] The second liquid LQ2, which has flown into the recovery
flow passage 46 formed in the annular portion 45B, is collected in
the recovery flow passage 46 formed in the shaft portion 45A, and
then the second liquid LQ2 flows into the second recovery flow
passage 44 formed in the barrel PK. The second liquid LQ2, which
has flown through the second recovery flow passage 44, is sucked
and recovered by the second liquid recovery section 41 via the
second recovery tube 43.
[0139] Next, an explanation will be made about a method for
exposing the substrate P with the image of the pattern of the mask
M by using the exposure apparatus EX constructed as described
above.
[0140] When the exposure is performed for the substrate P, the
control unit CONT supplies the second liquid LQ2 from the second
liquid supply mechanism 30 to the second space K2. When the second
liquid supply mechanism 30 supplies the second liquid LQ2, the
space between the second optical element LS2 and the upper surface
T2 of the first optical element LS1 is filled with the second
liquid LQ2 so that only the partial area of the upper surface T2 of
the first optical element LS1, which includes the predetermined
area AR' through which the exposure light beam EL passes, becomes
the second liquid immersion area LR2. The second liquid LQ2, which
is supplied from the second liquid supply mechanism 30, locally
forms the second liquid immersion area LR2 which is greater than
the predetermined area AR' and which is smaller than the upper
surface T2, on a part of the upper surface T2 including the
predetermined area AR'. After the second liquid immersion area LR2
is formed, the control unit CONT stops the supply of the second
liquid LQ2 by the second liquid supply mechanism 30. The second
liquid LQ2 between the first optical element LS1 and the second
optical element LS2 is retained by the surface tension, and the
second liquid immersion area LR2 is maintained.
[0141] After the substrate P is loaded on the substrate stage PST
at a load position, the substrate stage PST, which holds the
substrate P, is moved by the control unit CONT to the position
under the projection optical system PL, i.e., the exposure
position. The control unit CONT supplies and recovers the first
liquid LQ1 by using the first liquid supply mechanism 10 and the
first liquid recovery mechanism 20 while optimally controlling the
supply amount of the first liquid LQ1 per unit time brought about
by the first liquid supply mechanism 10 and the recovery amount of
the first liquid LQ1 per unit time brought about by the first
liquid recovery mechanism 20 in the state in which the substrate
stage PST is opposed to the first optical element LS1 of the
projection optical system PL. And the control unit CONT forms the
first liquid immersion area LR1 of the first liquid LQ1 on at least
the optical path for the exposure light beam EL included in the
first space K1, and fills the optical path for the exposure light
beam EL with the first liquid LQ1.
[0142] In this arrangement, reference members (measuring members),
which are provided with reference marks to be measured, for
example, by a substrate alignment system as disclosed in Japanese
Patent Application Laid-open No. 4-65603 and a mask alignment
system as disclosed in Japanese Patent Application Laid-open No.
7-176468, are provided at predetermined positions on the substrate
stage PST. Further, for example, an uneven illuminance sensor as
disclosed, for example, in Japanese Patent Application Laid-open
No. 57-117238, a spatial image-measuring sensor as disclosed, for
example, in Japanese Patent Application Laid-open No. 2002-14005,
and a radiation amount sensor (illuminance sensor) as disclosed,
for example, in Japanese Patent Application Laid-open No. 11-16816
are provided as optical measuring sections at predetermined
positions on the substrate stage PST. Before the exposure process
is performed for the substrate P, the control unit CONT performs
the measurement of the marks on the reference members and/or
various types of measuring operations by using the optical
measuring sections. The control unit CONT performs the alignment
process for the substrate P and the process for adjusting
(calibrating) the image formation characteristic of the projection
optical system PL on the basis of the measurement results. For
example, when the measuring operation by using the optical
measuring section is performed, the control unit CONT moves the
substrate stage PST relative to the first liquid immersion area LR1
of the first liquid LQ1 by moving the substrate stage PST in the XY
directions to arrange the first liquid immersion area LR1 of the
first liquid LQ1 on the optical measuring section so that the
measuring operation is performed in this state via the first liquid
LQ1 and the second liquid LQ2. The measurement of the reference
mark measured by the mask alignment system and/or the various types
of the calibration processes using the optical measuring sections
may be performed before the substrate P as the exposure objective
is placed on the substrate stage PST.
[0143] After the alignment process and the calibration process are
performed as described above, the control unit CONT projects the
image of the pattern of the mask M onto the substrate P to expose
the substrate P therewith by radiating the exposure light beam EL
onto the substrate P via the projection optical system PL, the
second liquid LQ2 of the second liquid immersion area LR2 formed on
the side of the upper surface T2 of the first optical element LS1,
and the first liquid LQ1 of the first liquid immersion area LR1
formed on the side of the lower surface T1 of the first optical
element LS1, while moving, in the X axis direction (scanning
direction), the substrate stage PST which supports the substrate P,
and while performing the recovery of the first liquid LQ1 from the
surface of the substrate P by using the first liquid recovery
mechanism 20 concurrently with the supply of the first liquid LQ1
onto the substrate P by using the first liquid supply mechanism 10.
The first liquid LQ1, which is supplied from the first liquid
supply mechanism 10, locally forms the first liquid immersion area
LR1 which is greater than the projection area AR and which is
smaller than the substrate P, on the part of the substrate P
including the projection area AR. The second liquid LQ2, which is
supplied from the second liquid supply mechanism 30, locally forms
the second liquid immersion area LR2 which is greater than the
predetermined area AR' and which is smaller than the upper surface
T2, on the part of the upper surface T2 including the predetermined
area AR' of the upper surface T2 of the first optical element
LS1.
[0144] During the exposure of the substrate P, the operation for
supplying the first liquid LQ1 and the operation for recovering the
first liquid LQ1 are continued by the first liquid immersion
mechanism 1. The optical path for the exposure light beam EL
between the first element and the substrate P is filled with the
first liquid LQ1, while maintaining the size and the shape of the
first liquid immersion area LR1 to be in a desired state. On the
other hand, during the exposure of the substrate P, the operation
for supplying the second liquid LQ2 and the operation for
recovering the second liquid LQ2 are not performed by the second
liquid immersion mechanism 2. That is, the exposure is performed
through the second liquid LQ2 in the pooled state (retained state
by the surface tension) in the second space K2. When the supply and
the recovery of the second liquid LQ2 are not performed during the
exposure of the substrate P, no vibration is generated by the
supply and/or the recovery of the second liquid LQ2 during the
exposure of the substrate P. Therefore, it is possible to avoid the
deterioration of the exposure accuracy which would be otherwise
caused by the vibration.
[0145] The second liquid LQ2 locally forms the second liquid
immersion area LR2 in only the partial area including the
predetermined area AR' through which the exposure light beam EL
passes, of the upper surface T2 of the first optical element LS1.
Accordingly, it is possible to avoid the leakage of the second
liquid LQ2 to the outside of the upper surface T2 of the first
optical element LS1. Therefore, it is possible to avoid the inflow
and the adhesion of the second liquid LQ2 with respect to the
barrel PK (first support section 91) for supporting the first
optical element LS1. It is possible to avoid the deterioration of
the barrel PK (first support section 91). Further, it is possible
to avoid the deterioration of any mechanical part and any electric
part disposed around the first optical element LS1, which would be
otherwise caused by the leaked second liquid LQ2.
[0146] The second liquid LQ2 makes no contact, for example, with
the barrel PK and/or the first support section 91, because the
second liquid LQ2 locally forms the second liquid immersion area
LR2 on the upper surface T2 of the first optical element LS1.
Therefore, it is possible to avoid the inconvenience such as the
mixing of any impurity including the metal ion or the like
generated, for example, from the barrel PK and the first support
section 91 with respect to the second liquid LQ2 for forming the
second liquid immersion area LR2. Therefore, the exposure process
and the measurement process can be satisfactorily performed in the
state in which the cleanness of the second liquid LQ2 is
maintained.
[0147] The exposure apparatus EX of this embodiment performs the
projection exposure onto the substrate P with the image of the
pattern of the mask M while moving the mask M and the substrate P
in the X axis direction (scanning direction). During the scanning
exposure, a part of the image of the pattern of the mask M is
projected into the projection area AR via the projection optical
system PL and the first and second liquids LQ1, LQ2 of the first
and second liquid immersion areas LR1, LR2. The mask M is moved at
the velocity V in the -X direction (or in the +X direction), in
synchronization with which the substrate P is moved at the velocity
.beta.V (.beta. represents the projection magnification) in the +X
direction (or in the -X direction) with respect to the projection
area AR. A plurality of shot areas are set on the substrate P.
After the exposure is completed for one shot area, the next shot
area is moved to the scanning start position in accordance with the
stepping movement of the substrate P. The scanning exposure process
is successively performed thereafter for the respective shot areas
while moving the substrate P in the step-and-scan manner.
[0148] In this embodiment, the first optical element LS1, which is
formed of the parallel flat plate, is arranged under the second
optical element LS2 having the lens function. However, the first
space K1 disposed on the side of the lower surface T1 of the first
optical element LS1 and the second space K2 of the first optical
element LS1 disposed on the side of the upper surface T2 are filled
with the first liquid LQ1 and the second liquid LQ2 respectively.
Accordingly, the reflection loss is reduced on the lower surface T3
of the second optical element LS2 and the upper surface T2 of the
first optical element LS1. The substrate P can be exposed
satisfactorily in the state in which the large image side numerical
aperture of the projection optical system PL is secured.
[0149] In this embodiment, the porous member 25 is inclined with
respect to the surface of the substrate P. In this arrangement, the
first liquid LQ1 is recovered via the inclined surface 26 of the
porous member 25 arranged in the first recovery port 22. In this
arrangement, the first liquid LQ1 is recovered via the first
recovery port 22 including the inclined surface 26. Further, the
land surface 75 and the inclined surface 26 are formed
continuously. In such a situation, when the substrate P is
subjected to the scanning movement at a predetermined velocity by a
predetermined distance in the +X direction with respect to the
first liquid immersion area LR1 from the initial state shown in
FIG. 8(a) (the state in which the first liquid immersion area LR1
of the first liquid LQ1 is formed between the land surface 75 and
the substrate P), the state as shown in FIG. 8(b) is obtained. The
component F1 to move obliquely in the upward direction along the
inclined surface 26 and the component F2 to move in the horizontal
direction are generated in the first liquid LQ1 of the first liquid
immersion area LR1 in the predetermined state after the scanning
movement as shown in FIG. 8(b). In this situation, the shape of the
interface (gas/liquid interface) LG between the first liquid LQ1 of
the first liquid immersion area LR1 and the space disposed outside
is maintained. Even when the substrate P is moved at a high
velocity with respect to the first liquid immersion area LR1, it is
possible to suppress any great change of the shape of the interface
LG.
[0150] The distance between the inclined surface 26 and the
substrate P is greater than the distance between the land surface
75 and the substrate P. That is, the space between the inclined
surface 26 and the substrate P is greater than the space between
the land surface 75 and the substrate P. Therefore, when the
substrate P is moved with respect to the first liquid immersion
area LR1, it is possible to make a distance L between an interface
LG' and the interface LG to be relatively small, the interface LG'
being brought about in the initial state shown in FIG. 8(a) and the
interface LG being brought about in the predetermined state after
the scanning movement shown in FIG. 8(b). Therefore, it is possible
to decrease the size of the first liquid immersion area LR1.
[0151] For example, as shown in FIG. 9(a), even if the land surface
75 and a lower surface 26' of the porous member 25 arranged in the
first recovery port 22 are formed continuously, the lower surface
26' of the porous member 25 is not inclined with respect to the
substrate P, and the lower surface 26' of the porous member 25 is
substantially in parallel to the surface of the substrate P, in
other words, even if the first recovery port 22 including the lower
surface 26' is not inclined, then the shape of the interface LG is
maintained when the substrate P is moved with respect to the first
liquid immersion area LR1. However, only the component F2 to move
in the horizontal direction is generated in the first liquid LQ1,
and the component (F1) to move in the upward direction is hardly
generated, because the lower surface 26' is not inclined. In such a
situation, the interface LG is moved by approximately the same
distance as the movement amount of the substrate P. Therefore, the
distance L between the interface LG' in the initial state and the
interface LG in the predetermined state after the scanning movement
has a relatively great value. Accordingly, the first liquid
immersion area LR1 is increased in size as well. On this
assumption, it is necessary that the nozzle member 70 should be
large-sized as well corresponding to the large first liquid
immersion area LR1. Further, it is also required to increase the
movement stroke of the substrate stage PST and the size of the
substrate stage PST itself according to the size of the first
liquid immersion area LR1. Consequently, the entire exposure
apparatus EX becomes huge in size. The tendency to increase the
size of the first liquid immersion area LR1 is conspicuous as the
scanning velocity of the substrate P with respect to the first
liquid immersion area LR1 is highly increased.
[0152] As shown in FIG. 9(b), when the distance between the lower
surface 26' and the substrate P is made greater than the distance
between the land surface 75 and the substrate P by providing the
difference in height between the land surface 75 and the first
recovery port 22 (lower surface 26' of the porous member 25), in
other words, when the space between the lower surface 26' and the
substrate P is made greater than the space between the land surface
75 and the substrate P, then the component F1' to move in the
upward direction is generated in the first liquid LQ1. Therefore,
it is possible to make the distance L to have a relatively small
value, and it is possible to suppress the large size of the first
liquid immersion area LR1. However, the shape of the interface LG
tends to be collapsed, because the difference in height is provided
between the land surface 75 and the lower surface 26', and the land
surface 75 and the lower surface 26' are not formed continuously.
When the shape of the interface LG is collapsed, there is such a
high possibility that any inconvenience may be caused, in which the
gas is mixed into the first liquid LQ1 of the first liquid
immersion area LR1, and any bubble is generated in the first liquid
LQ1. For example, when the substrate P is scanned at a high
velocity in the +X direction, then the presence of the difference
in height causes the collapse of the shape of the interface LG, and
the component F1' to move in the upward direction is further
increased. As a result, the thickness is thinned for the first
liquid LQ1 in the area disposed at the position most deviated
toward the +X side of the first liquid immersion area LR1. When the
substrate P is moved in the -X direction (subjected to the reverse
scanning) in this state, there is such a high possibility that a
phenomenon arises to break the first liquid LQ1 into portions. If
the broken liquid (see the symbol LQ' in FIG. 9(b)) remains, for
example, on the substrate P, an inconvenience arises such that any
adhesion trace (so-called water mark) is formed on the substrate P
due to the vaporization of the liquid LQ'. When the shape of the
interface LG is collapsed, then the first liquid LQ1 outflows to
the outside of the substrate P, and there is such a high
possibility to cause any inconvenience including, for example, the
rust and/or the electric leakage in relation to the peripheral
members and the equipment as well. The possibility of the
occurrence of the inconvenience as described above is increased as
the scanning velocity is highly increased for the substrate P with
respect to the first liquid immersion area LR1.
[0153] In this embodiment, the first recovery port 22 of the first
liquid immersion mechanism 1 (first liquid recovery mechanism 20)
is formed on the inclined surface 26 opposed to the surface of the
substrate P. Therefore, even when the substrate P and the first
liquid immersion area LR1 formed on the image plane side of the
projection optical system PL are relatively moved, then it is
possible to maintain the shape of the interface LG between the
first liquid LQ1 of the first liquid immersion area LR1 and the
space disposed outside, and it is possible to maintain the desired
state for the shape of the first liquid immersion area LR1.
Therefore, it is possible to avoid the inconvenience which would be
otherwise caused, for example, such that any bubble is generated in
the first liquid LQ1, the liquid cannot be recovered sufficiently,
and the liquid outflows. When the first recovery port 22 is
provided on the inclined surface 26, it is possible to suppress the
movement amount of the interface LG. Accordingly, it is possible to
decrease the size of the first liquid immersion area LR1.
Therefore, it is also possible to realize the compact size of the
entire exposure apparatus EX.
[0154] When the substrate P is scanned at a high velocity, there is
such a high possibility that the first liquid LQ1 of the first
liquid immersion area LR1 outflows to the outside and/or the first
liquid LQ1 of the first liquid immersion area LR1 is scattered to
the surroundings. However, it is possible to suppress the leakage
of the first liquid LQ1, because the wall portion 76 is provided at
the circumferential edge of the inclined surface 26. That is, when
the wall portion 76 is provided at the circumferential edge of the
porous member 25, the buffer space is formed inside the wall
portion 76. Therefore, even when the liquid LQ arrives at the inner
side surface of the wall portion 76, the liquid LQ, which forms the
liquid immersion area AR2, is expanded in the buffer space disposed
inside the wall portion 76. Accordingly, it is possible to more
reliably avoid the leakage of the liquid LQ to the outside of the
wall portion 76.
[0155] The part of the land surface 75 (lower surface of the bottom
plate portion 72D) is arranged under the end surface T1 of the
projection optical system PL to surround the projection area AR1.
Therefore, the small gap, which is formed between the part of the
land surface 75 (lower surface of the bottom plate portion 72D) and
the surface of the substrate P, is formed in the vicinity of the
projection area to surround the projection area. Accordingly, it is
possible to continuously maintain the small liquid immersion area
which is necessary and sufficient to cover the projection area AR1.
Therefore, it is possible to realize the compact size of the entire
exposure apparatus EX, while suppressing the inconvenience
including, for example, the outflow of the liquid LQ and the mixing
of the gas into the liquid LQ of the liquid immersion area AR2,
even when the substrate P is moved (scanned) at a high velocity.
Further, the liquid supply port 12 is arranged outside the part of
the land surface 75 (lower surface of the bottom plate portion
72D). Therefore, it is possible to prevent the gas (bubble) from
mixing into the liquid LQ which forms the liquid immersion area
AR2. Even when the substrate P is moved at a high velocity, it is
possible to continuously fill the optical path for the exposure
light beam EL with the liquid.
[0156] In the embodiment described above, the inclined surface 26
is formed by attaching the thin plate-shaped porous member 25
obliquely with respect to the substrate P. Alternatively, an
inclined surface may be provided on the lower surface of the nozzle
member 70 so that the spacing distance with respect to the surface
of the substrate P is increased at positions separated farther from
the optical axis AX of the exposure light beam EL, and the liquid
recovery port 22 may be formed at a predetermined position (in a
predetermined area) of the inclined surface. The porous member 25
may be provided for the liquid recovery port 22.
[0157] In this embodiment, the porous member 25 is arranged in the
first recovery port 22. However, it is also allowable that the
porous member 25 is absent or omitted. Also in this case, for
example, an inclined surface may be provided on the lower surface
of the nozzle member 70 so that the spacing distance with respect
to the surface of the substrate P is increased at positions
separated farther from the optical axis AX of the exposure light
beam EL, and the liquid recovery port may be provided at a
predetermined position of the inclined surface. Accordingly, it is
possible to maintain the shape of the interface LG, and it is
possible to avoid the inconvenience which would be otherwise
caused, for example, such that any bubble is generated in the first
liquid LQ1 of the first liquid immersion area LR1. Further, it is
also possible to decrease the size of the first liquid immersion
area LR1.
[0158] When the exposure for the substrate P is completed, then the
control unit CONT stops the supply of the first liquid LQ1 having
been performed by the first liquid supply mechanism 10, and the
first liquid LQ1 in the first liquid immersion area LR1 (first
liquid LQ1 in the first space K1) is recovered by using, for
example, the first liquid recovery mechanism 20. Further, the
control unit CONT recovers the first liquid LQ1 remaining on the
substrate P and on the substrate stage PST, by using, for example,
the first recovery port 22 of the first liquid recovery mechanism
20.
[0159] As explained with reference to FIG. 7, the control unit CONT
recovers, via the second recovery ports 42, the second liquid LQ2
in the second liquid immersion area LR2 formed in the second space
K2 after the completion of the exposure for the substrate P.
[0160] After the first liquid LQ1 on the substrate P and the second
liquid LQ2 on the upper surface T2 of the first optical element LS1
are recovered, the substrate stage PST, which supports the
substrate P, is moved to an unload position by the control unit
CONT to unload the substrate P.
[0161] The substrate P, which is next to be subjected to the
exposure process, is loaded on the substrate stage PST. The control
unit CONT supplies the second liquid LQ2 to the second space K2 in
order to expose the substrate P loaded on the substrate stage PST.
The substrate P is exposed in accordance with the same sequence as
that described above.
[0162] This embodiment is constructed such that the second liquid
LQ2 in the second space K2 is exchanged for every substrate P to be
exposed. However, the second liquid LQ2 in the second space K2 may
be exchanged at every predetermined time interval, every
predetermined number of substrates to be processed, or every lot,
for example, provided that the deterioration of the cleanness and
the temperature change of the liquid LQ2 in the second space K2 are
in such an extent that the exposure accuracy is not affected
thereby.
[0163] The supply and the recovery of the second liquid LQ2 may be
performed continuously during the exposure of the substrate P or
before or after the exposure as well. When the supply and the
recovery of the second liquid LQ2 are performed continuously, the
second space K2 can be always filled with the temperature-managed
and clean second liquid LQ2. On the other hand, when the exposure
is performed in the state in which the second liquid LQ2 is pooled
in the second space K2, and the second liquid LQ2 is exchanged
intermittently for the second space K2 as in this embodiment, the
vibration is not caused by the supply and the recovery of the
second liquid LQ2 during the exposure of the substrate P as
described above. In the case of the procedure in which the supply
and the recovery of the second liquid LQ2 are continuously
performed during the exposure of the substrate P, for example, if
the supply amount and the recovery amount of the second liquid LQ2
per unit time are unstable, the following possibility arises. That
is, the second liquid immersion area LR2 is enormously expanded,
the second liquid LQ2 is subjected to the outflow or the scattering
at the inside of the barrel PK, and the damage is increased. If the
supply amount and the recovery amount of the second liquid LQ2 per
unit time are unstable, any inconvenience arises such that the
second liquid immersion area LR2 is exhausted, and the exposure
accuracy is deteriorated. Therefore, when the second liquid LQ2 is
exchanged intermittently for the second space K2, then it is
possible to form the second liquid immersion area LR2 in a desired
state, and it is possible to avoid the occurrence of the
inconvenience as described above.
[0164] There is such a possibility that the first liquid LQ1 may be
polluted by being contaminated, for example, with any impurity
generated from the substrate P, including, for example, any foreign
matter resulting, for example, from the photosensitive agent
(photoresist), mixing into the first liquid LQ1 of the first liquid
immersion area LR1 (first space K1). There is such a possibility
that the lower surface T1 of the first optical element LS1 may be
polluted with the contaminated first liquid LQ1, because the first
liquid LQ1 in the first liquid immersion area LR1 also makes
contact with the lower surface T1 of the first optical element LS1.
Further, there is also such a possibility that any impurity
floating in the air may adhere to the lower surface T1 of the first
optical element LS1 exposed on the image plane side of the
projection optical system PL.
[0165] In this embodiment, the first optical element LS1 can be
easily attached and detached (exchangeable) with respect to the
barrel PK. Therefore, the deterioration of the exposure accuracy
and the measurement accuracy via the projection optical system PL,
which would be otherwise caused by the pollution of the optical
element, can be avoided by exchanging only the polluted first
optical element LS1 with the clean first optical element LS1. On
the other hand, the second liquid LQ2 in the second space K2 does
not make any contact with the substrate P. Further, the second
space K2 is the substantially closed space surrounded by the first
optical element LS1, the second optical element LS2, and the barrel
PK. Therefore, the impurity floating in the air is hardly mixed
into the second liquid LQ2 in the second space K2, and the impurity
hardly adheres to the lower surface T3 of the second optical
element LS2 and the upper surface T2 of the first optical element
LS1. Therefore, the cleanness is maintained for the lower surface
T3 of the second optical element LS2 and the upper surface T2 of
the first optical element LS1. Therefore, when only the first
optical element LS1 is exchanged, then it is possible to avoid, for
example, the deterioration of the transmittance of the projection
optical system PL, and it is possible maintain the exposure
accuracy and the measurement accuracy.
[0166] An arrangement is also conceived, in which the liquid of the
first liquid immersion area LR1 is allowed to make contact with the
second optical element LS2 without providing the first optical
element LS1 formed of the parallel flat plate. However, if it is
intended to increase the image side numerical aperture of the
projection optical system PL, then it is necessary to increase the
effective diameter of the optical element, and it is inevitable
that the optical element LS2 has a large size. The nozzle member 70
as described above and the various types of the measuring units
such as the alignment system (although not shown) are arranged
around the optical element LS2. Therefore, if such a large-sized
optical element LS2 is exchanged, then the operability is lowered,
and the operation is difficult to be performed. Further, the
optical element LS2 has the refractive power (lens function).
Therefore, it is necessary that the optical element LS2 should be
attached to the barrel PK with the high positioning accuracy in
order to maintain the optical characteristic (image formation
characteristic) of the entire projection optical system PL.
Therefore, it is not preferable to frequently attach and detach
(exchange) the optical element LS2 as described above with respect
to the barrel PK in view of the maintenance of the optical
characteristic of the projection optical system PL (positioning
accuracy of the optical element LS2) as well. This embodiment is
constructed such that the relatively small-sized parallel flat
plate is provided as the first optical element LS1, and the first
optical element LS1 is exchanged. Therefore, the operability is
satisfactory, and the exchange operation can be performed with
ease. It is also possible to maintain the optical characteristic of
the projection optical system PL. Further, the exposure apparatus
EX is provided with the first and second liquid immersion
mechanisms 1, 2 which are capable of independently supplying and
recovering the first and second liquid LQ1, LQ2 with respect to the
first space K1 disposed on the side of the lower surface T1 of the
first optical element LS1 and the second space K2 disposed on the
side of the upper surface T2 of the first optical element LS1
respectively. Accordingly, the exposure light beam EL, which is
radiated from the illumination optical system IL, is successfully
allowed to satisfactorily arrive at the substrate P arranged on the
image plane side of the projection optical system PL while
maintaining the cleanness of the first and second liquid LQ1,
LQ2.
[0167] As explained above, the space between the substrate P and
the lower surface T1 of the first optical element LS1 is filled
with the first liquid LQ1, and the space between the second optical
element LS2 and the upper surface T2 of the first optical element
LS1 is filled with the second liquid LQ2. Accordingly, the exposure
light beam EL, which has passed through the mask M, can be allowed
to satisfactorily arrive at the substrate P, and the substrate P
can be exposed satisfactorily. The second liquid immersion area LR2
of the second liquid LQ2 is locally formed on the side of the upper
surface T2 of the first optical element LS1. Therefore, it is
possible to avoid the inconvenience which would be otherwise
caused, for example, such that the second liquid LQ2 of the second
liquid immersion area LR2 is polluted due to the contact of the
second liquid LQ2, for example, with the barrel PK, and the barrel
PK including the first support section 91 is deteriorated by the
second liquid LQ2. When the second liquid immersion area LR2 is
formed locally, it is possible to avoid the inconvenience which
would be otherwise caused such that the second liquid LQ2 leaks to
the outside of the barrel PK. Therefore, when any seal mechanism is
provided in order to avoid the leakage of the second liquid LQ2,
the seal mechanism can be constructed simply and conveniently.
Alternatively, the seal mechanism may be omitted.
[0168] The outer diameter D3 of the lower surface T3 of the second
optical element LS2 opposed to the first optical element LS1 is
smaller than the outer diameter D2 of the upper surface T2 of the
first optical element LS1. Therefore, the second liquid immersion
area LR2, which has the size corresponding to the lower surface T3
of the second optical element LS2, can be formed locally and
satisfactorily on the upper surface T2 of the first optical element
LS1. It is possible to further reliably avoid the leakage of the
second liquid LQ2 from the circumference of the upper surface T2 of
the first optical element LS1.
[0169] In the embodiment described above, the upper surface T2 of
the first optical element LS1 is provided with the second area HR2
having the liquid repellence in order to avoid, for example, the
leakage of the second liquid LQ2. However, as schematically shown
in FIG. 10, a bank portion DR may be provided to surround the first
area HR1 on the upper surface T2 of the first optical element LS1.
Also in this way, it is possible to avoid the leakage of the second
liquid LQ2 of the second liquid immersion area LR2 formed in the
first area HR1. In this arrangement, the optical path for the
exposure light beam EL in the second space K2 may be filled with
the second liquid LQ2 by storing a predetermined amount of the
second liquid LQ2 in the bank portion DR. The second liquid LQ2,
which has overflowed from the bank portion DR or which is likely to
overflow, may be recovered.
[0170] In the embodiment described above, the liquid recovery port
is provided on the inclined surface of the lower surface of the
nozzle member 70 (lower surface of the porous member). However,
when the leakage of the liquid LQ is successfully suppressed, the
liquid recovery port may be provided on the surface which is
substantially parallel to (flush with) the land surface 75, without
forming the inclined surface on the lower surface of the nozzle
member 70. That is, the first liquid recovery port 22 may be
provided as shown in FIGS. 9(a) and 9(b) provided that the liquid
LQ1 can be recovered without causing any leakage even when the
movement velocity of the substrate P is increased, for example,
when the contact angle of the liquid LQ1 with respect to the
substrate P is large, or when the ability to recover the liquid LQ1
from the first recovery port 22 by the first recovery mechanism 20
is excellent.
[0171] In the embodiment described above, the wall portion 76 is
provided at the circumferential edge of the inclined surface (lower
surface of the porous member) formed on the lower surface of the
nozzle member 70. However, when the leakage of the liquid LQ is
successfully suppressed, it is also possible to omit the wall
portion 76.
[0172] In the embodiment described above, the part of the land
surface (flat portion) 75 of the nozzle member 70 is formed between
the projection optical system PL and the substrate P, and the
inclined surface (lower surface of the porous member) is formed at
the outside thereof. However, the part of the land surface may be
arranged outside (around) the end surface T1 of the projection
optical system PL with respect to the optical axis of the
projection optical system PL, instead of being arranged under the
projection optical system PL. In this arrangement, the land surface
75 may be substantially flush with the end surface T1 of the
projection optical system PL. Alternatively, the position of the
land surface 75 in the Z axis direction may be separated in the +Z
direction or in the -Z direction from the end surface T1 of the
projection optical system PL.
[0173] In the embodiment described above, the liquid supply port 12
is formed to be annular slit-shaped to surround the projection area
AR1. However, a plurality of supply ports, which are separated from
each other, may be provided. In this arrangement, the positions of
the supply ports are not specifically limited. The supply ports may
be provided one by one on the both sides of the projection area AR1
(on the both sides in the X axis direction or on the both sides in
the Y axis direction). Alternatively, the supply ports may be
provided one by one (four in total) on the both sides of the
projection area AR1 in the X axis direction and the Y axis
direction. It is also allowable that only one supply port may be
provided at a position separated in a predetermined direction with
respect to the projection area AR1 provided that the desired liquid
immersion area AR2 can be formed. In the embodiment described
above, the first supply port 12 is provided at the position opposed
to the substrate P. However, there is no limitation thereto. For
example, the first liquid LQ1 may be supplied from the space
between the first optical element LS1 and the bottom plate portion
72D. Also in this arrangement, the supply port may be provided to
surround the optical path for the exposure light beam EL.
Alternatively, the supply ports may be provided one by one on the
both sides of the optical path for the exposure light beam EL. When
the liquid LQ is supplied from a plurality of supply ports, the
amounts of the liquid LQ to be supplied from the respective supply
ports may be adjustable so that the liquid may be supplied in
different amounts from the respective supply ports.
[0174] As shown in FIG. 11, a plurality of fin members 150 may be
formed on the inclined surface formed on the lower surface of the
nozzle member 70 (lower surface of the porous member 25). The fin
member 150 is substantially triangular as viewed in a side view. As
shown in the side sectional view in FIG. 11, the fin members 150
are arranged in the buffer space formed on the inner side of the
wall portion 76 and on the lower surface of the porous member 25.
The fin member 150 is attached to the inner side surface of the
wall portion 76 radially so that the longitudinal direction thereof
is directed outwardly. In this arrangement, the plurality of fin
members 150 are separated from each other, and the spaces are
formed between the respective fin members 150. When the plurality
of fin members 150 are arranged as described above, it is possible
to increase the liquid contact area on the inclined surface (lower
surface of the porous member 25) formed on the lower surface of the
nozzle member 70. Therefore, it is possible to improve the
performance to retain the liquid LQ on the lower surface of the
nozzle member 70. The plurality of fin members 150 may be provided
at equal intervals. Alternatively, the plurality of fin members 150
may be provided at unequal intervals. For example, the intervals of
the fin members 150 arranged on the both sides in the X axis
direction with respect to the projection area AR1 may be set to be
smaller than the intervals of the fin members 150 arranged on the
both sides in the Y axis direction with respect to the projection
area AR1. It is preferable that the surface of the fin member 150
is liquid-attractive with respect to the liquid LQ. The fin member
150 may be formed by applying the "GOLDEP" treatment or the "GOLDEP
WHITE" treatment to stainless steel (for example, SUS 316).
Alternatively, the fin member 150 can be formed of, for example,
glass (silica glass) as well.
[0175] Next, another embodiment will be explained with reference to
FIG. 12. In the following description, the same or equivalent
constitutive portions as those of the embodiment described above
are designated by the same reference numerals, any explanation of
which will be simplified or omitted.
[0176] Also in this embodiment, each of the first optical element
LS1 and the second optical element LS2 is supported in the
substantially stationary state by the barrel PK with respect to the
optical path for the exposure light beam EL.
[0177] With reference to FIG. 12, the first optical element LS1 is
a parallel flat plate in which the lower surface T1 and the upper
surface T2 are in parallel to each other. The lower surface 71 and
the upper surface T2 are substantially parallel to the XY plane.
The first optical element LS1 is supported by a first support
section 91 provided at the lower end of the barrel PK. A flange
portion F1, which serves as a support objective portion, is
provided at an upper portion of the first optical element LS1. The
first support section 91 supports the first optical element LS1 by
supporting the lower surface T5 of the flange portion F1. In this
arrangement, the lower surface T5 of the flange portion F1 is also
substantially parallel to the XY plane, and the lower surface T5 of
the flange portion F1 is formed around the lower surface T1 of the
first optical element LS1.
[0178] The distance (thickness) H1 between the lower surface T1 and
the upper surface T2 of the first optical element LS1 on the
optical axis AX of the projection optical system PL is not less
than 15 mm. As also clarified from FIG. 12, the distance H1 between
the lower surface T1 and the upper surface T2 of the first optical
element LS1 on the optical axis AX is greater than the distance
between the substrate P and the lower surface T1 of the first
optical element LS1. That is, the thickness of the first optical
element LS1 on the optical axis AX is formed to be thicker than the
liquid LQ1. Also in this embodiment, the thickness of the liquid
LQ1 is about 3 mm. The distance between the land surface 75 and the
substrate P is about 1 mm. In this embodiment, the thickness H1 of
the first optical element LS1 is about 15 mm. However, there is no
limitation thereto. The thickness H1 can be set within a range of
about 15 mm to 20 mm.
[0179] The second optical element LS2 is supported by a second
support section 92 which is provided over the first support section
91 in the barrel PK. A flange portion F2, which serves as a support
objective portion, is provided at an upper portion of the second
optical element LS2. The second support section 92 supports the
second optical element LS2 by supporting the flange portion F2. The
lower surface T3 of the second optical element LS2 is formed to be
flat or planar. The lower surface T3 of the second optical element
LS2 supported by the second support section 92 is substantially
parallel to the upper surface T2 of the first optical element LS1
supported by the first support section 91. On the other hand, the
upper surface T4 of the second optical element LS2 is formed to be
convex toward the object plane (toward the mask M), and has a
positive refractive power.
[0180] The first optical element LS1 can be easily attached and
detached with respect to the first support section 91 of the barrel
PK. That is, the first optical element LS1 is provided
exchangeably. The second optical element LS2, which has the
refractive power (lens function), is supported by the second
support section 92 of the barrel PK in a state of being
satisfactorily positioned.
[0181] The upper surface T2 of the first optical element LS1 having
the flange portion F1 is formed to be sufficiently greater than the
lower surface T3 of the second optical element LS2. The outer
diameter D3 of the lower surface T3 of the second optical element
LS2 opposed to the first optical element LS1 is smaller than the
outer diameter D2 of the upper surface T2 of the first optical
element LS1. The second liquid immersion area LR2 is locally formed
by the second liquid LQ2 on the upper surface T2 of the first
optical element LS1.
[0182] The distance H1 between the lower surface T1 and the upper
surface T2 of the first optical element LS1 is longer than the
distance H2 between the upper surface T2 of the first optical
element LS1 and the lower surface T5 of the flange portion. F1. In
this embodiment, the outer diameter D2 of the upper surface T2 of
the first optical element LS1 having the flange portion F1 is set
to be not less than twice the outer diameter D1 of the lower
surface T1 of the first optical element LS1. The first optical
element LS1, which has the lower surface T5 of the flange portion
F1 supported by the first support section 91, has the lower portion
which is exposed (which protrudes) downwardly from the lower
surface PKA of the barrel PK.
[0183] At least a part of the nozzle member 70 is arranged in the
space formed between the substrate P and the flange portion F1 of
the first optical element LS1 and the first support section 91 for
supporting the flange portion F1. In other words, the flange
portion (support objective portion) F1 of the first optical element
LS1 and the first support section 91 for supporting the flange
portion F1 are provided over (above) the nozzle member 70. The
upper surface 70B of the nozzle member 70 is opposed to the lower
surface T5 of the flange portion F1 of the first optical element
LS1 and the lower surface PKA of the barrel PK. An inner side
surface 70T of the nozzle member 70 is opposed to a side surface C1
of the first optical element LS1.
[0184] The nozzle member 70, which is arranged under the flange
portion F1, is arranged closely to the side surface C1 of the first
optical element LS1. The first supply port 12, which is provided
for the nozzle member 70, is provided closely to the projection
area AR. The first recovery port 22, which is formed to surround
the projection area AR, is also provided closely to the projection
area AR. The outer diameter D22 of the first recovery port 22 is
provided to be smaller than the outer diameter D2 of the upper
surface T2 of the first optical element LS1.
[0185] The bottom plate portion 72D, which forms the land surface
75, is arranged to creep into the space under the lower surface T1
of the first optical element LS1.
[0186] As explained above, the outer diameter D2 of the upper
surface T2 of the first optical element LS1 is greater than the
outer diameter D1 of the lower surface T1. More specifically, the
outer diameter D2 of the upper surface T2 is not less than twice
the outer diameter D1 of the lower surface T1. Therefore, when the
first optical element LS1 is supported by the first support section
91, the first support section for supporting the first optical
element LS1 can be provided at the position separated far from the
optical axis AX of the first optical element LS1 in relation to the
horizontal direction, by allowing the first support section 91 to
support the end portion of the upper surface T2 (flange portion
F1). Therefore, it is possible to secure the space between the
first support section 91 and the side surface C1 of the first
optical element LS1 (space around the first optical element LS1).
The nozzle member 70, which is provided for the first liquid LQ1,
can be arranged in the space. This arrangement is not directed to
only the nozzle member 70. It is also possible to improve the
degree of freedom of the arrangement, for example, when various
measuring units such as the alignment system are arranged. It is
also possible to improve the degree of freedom of the design of the
measuring unit or the like to be arranged in the space, because the
space is sufficiently secured. The outer diameter D2 of the upper
surface T2 of the first optical element LS1 is not less than twice
the outer diameter D1 of the lower surface T1, and the outer
diameter D1 of the lower surface T1 of the first optical element
LS1 is sufficiently smaller than the upper surface T2. Therefore,
the first liquid LQ1 of the first liquid immersion area LR1 formed
by the first liquid immersion mechanism 1 is made to have a contact
with the lower surface T1, and thus the size of the first liquid
immersion area LR1 can be decreased depending on the lower surface
T1. Therefore, it is possible to avoid the inconvenience of the
enormous increase in size of the entire exposure apparatus EX which
would be otherwise caused by the enormous increase in size of the
first liquid immersion area LR1. The size (position) of the first
recovery port 22 is regarded as one of the factors to determine the
size of the first liquid immersion area LR1. However, the outer
diameter D22 of the first recovery port 22 is smaller than the
outer diameter D2 of the upper surface T2 of the first optical
element LS1. Therefore, it is possible to decrease the size of the
first liquid immersion area LR1.
[0187] The distance H1 between the lower surface T1 and the upper
surface T2 of the first optical element LS1 is greater than the
distance between the first optical element LS1 and the substrate P.
More specifically, the distance H1 is not less than 15 mm, and the
first optical element LS1 is thick. Accordingly, when the first
optical element LS1 is supported by the first support section 91,
the first support section 91, which supports the first optical
element LS1, can be provided at the position separated far from the
lower surface T1 of the first optical element LS1 in relation to
the vertical direction, by allowing the first support section 91 to
support the portion disposed in the vicinity of the upper surface
T2 of the first optical element LS1, i.e., the flange portion F1
for forming the upper surface T2 in this embodiment. Therefore, it
is possible to secure the space between the substrate P and the
lower surface T5 of the flange portion F1 of the first optical
element LS1 (space around the first optical element LS1). The
nozzle member 70 can be arranged in the space. This arrangement is
not directed to only the nozzle member 70. It is also possible to
improve the degree of freedom of the arrangement, for example, when
various measuring units such as the alignment system are arranged.
It is also possible to improve the degree of freedom of the design.
The nozzle member 70 can be arranged closely to the side surface C1
of the first optical element LS1. Accordingly, it is possible to
realize the compact size of the nozzle member 70, and it is
possible to decrease the size of the first liquid immersion area
LR1 of the first liquid LQ1. Therefore, it is possible to avoid the
inconvenience of the enormous increase in size of the entire
exposure apparatus EX which would be otherwise caused by the
enormous expansion of the first liquid immersion area LR1.
[0188] The thickness (distance H1) of the first optical element LS1
is thicker than that of the first liquid LQ1 disposed between the
first optical element LS1 and the substrate P. More specifically,
the distance H1 is not less than 15 mm. Accordingly, it is possible
to suppress the change of the shape of the first optical element
LS1 which would be otherwise caused by the force received from the
liquid. Therefore, it is possible to maintain the high image
formation performance of the projection optical system PL.
[0189] In the embodiment explained with reference to FIG. 12, the
first optical element LS1 satisfies both of the condition in which
the distance (thickness) H1 is not less than 15 mm and the
condition in which the outer diameter D2 of the upper surface T2 is
not less than twice the outer diameter D1 of the lower surface T1.
However, the first optical element LS1 may be constructed under a
condition in which any one of the foregoing conditions is
satisfied. Even in the case of the arrangement in which any one of
the conditions is satisfied, it is possible to realize the compact
size of the nozzle member 70, and it is possible to avoid the
enormous expansion of the first liquid immersion area LR1.
[0190] In the embodiment explained with reference to FIG. 12, the
first optical element LS1 has the conical side surface in which the
outer diameter is decreased at positions separated farther from the
flange portion F1 toward the lower surface T1. However, the shape
of the first optical element LS1 is not limited to this shape. For
example, a columnar first optical element LS1 may also be adopted,
in which the side surface has the outer diameter D1 while
maintaining the flange portion F1. In another viewpoint, the
diameter of the exposure light beam EL in the scanning direction (X
direction) is smaller than the diameter in the non-scanning
direction (Y direction) in the first optical element LS1.
Therefore, a first optical element may also be adopted, wherein the
cross section, which is taken along the XY plane, is an ellipse
having a small diameter in the X direction, wherein the first
optical element has a side surface such that the outer diameter is
decreased at positions separated farther from the flange portion F1
toward the lower surface T1. The shape and the arrangement of the
nozzle member can be changed in conformity therewith.
[0191] Also in this embodiment, the distance between the substrate
P and the lower surface T1 of the first optical element LS1 is
about 3 mm, the distance between the land surface 75 and the
substrate P is about 1 mm, and the distance between the upper
surface T2 of the first optical element LS1 and the lower surface
T3 of the second optical element LS2 is about 3 mm. However, the
distance between the substrate P and the lower surface T1 of the
first optical element LS1 can be set within a range of 1 to 5 mm,
considering the absorption of the exposure light beam EL by the
liquid LQ1 and the flow of the liquid LQ1 in the first space K1, in
the same manner as in the embodiment described above. The distance
between the land surface 75 and the substrate P can be also set
within a range of 0.5 to 1 mm. The distance between the upper
surface T2 of the first optical element LS1 and the lower surface
T3 of the second optical element LS2 can be also set within a range
of 0.5 to 5 mm considering the flow of the liquid LQ2.
[0192] In this embodiment, the barrel PK is constructed by
combining a plurality of divided barrels (sub-barrels). The
sub-barrel, which includes the first support section 91 for
supporting the first optical element LS1, can be attached and
detached with respect to the partial barrel for supporting the
other optical elements L2 to L7. The first optical element LS1
having the flange portion F1 is exchangeable by being detached from
the partial barrel together with the sub-barrel.
[0193] When the first optical element LS1 of the embodiment of the
present invention is used, it is also allowable to adopt an
arrangement in which no second liquid immersion area LR2 is formed
as shown in FIG. 13. The first optical element LS1 shown in FIG. 13
is the optical element which is closest to the image plane of the
projection optical system PL. The upper surface T2 of the first
optical element LS1 is formed to be convex toward the object plane,
which has a positive refractive index. The first liquid LQ1 of the
first liquid immersion area LR1 makes contact with the first
optical element LS1. In such a situation, when the first optical
element LS1 satisfies at least any one of the condition in which
the distance H1 between the lower surface T1 and the upper surface
T2 on the optical axis AX is not less than 15 mm and the condition
in which the outer diameter D2 of the upper surface T2 is not less
than twice the outer diameter D1 of the lower surface T1, then it
is possible to realize the compact size of the nozzle member 70,
and it is possible to avoid the enormous expansion of the first
liquid immersion area LR1.
[0194] In the respective embodiments described above, the second
liquid immersion area LR2 of the second liquid LQ2 is locally
formed on the upper surface T2 of the first optical element LS1.
However, as shown in FIG. 14, an arrangement is also adoptable, in
which the second liquid LQ2 of the second liquid immersion area LR2
is arranged in the substantially entire region of the upper surface
T2.
[0195] Also in the embodiment shown in FIG. 14, the first optical
element LS1 satisfies at least any one of the condition in which
the distance H1 between the lower surface T1 and the upper surface
T2 on the optical axis AX is not less than 15 mm and the condition
in which the outer diameter D2 of the upper surface T2 is not less
than twice the outer diameter D1 of the lower surface T1. In the
same manner as the embodiment explained, for example, with
reference to FIG. 12, the first optical element LS1 is exposed
(allowed to protrude) downwardly from the barrel PK, and the nozzle
member 70 is arranged closely to the first optical element LS1.
[0196] A second supply port 32, which constructs a part of the
second liquid supply mechanism 30, is provided on the inner side
surface PKC of the barrel PK. The second supply port 32 is formed
at the position in the vicinity of the second space K2 on the inner
side surface PKC of the barrel PK. The second supply port 32 is
provided on the +X side with respect to the optical axis AX of the
projection optical system PL. The second liquid LQ2, which is fed
from the second liquid supply section 31, is discharged by the
second supply port 32 substantially in parallel to the upper
surface T2 of the first optical element LS1, i.e., substantially in
parallel to the XY plane (in the lateral direction). The force,
which is exerted by the supplied second liquid LQ2, for example, on
the first and second optical elements LS1, LS2, can be reduced,
because the second supply port 32 discharges the second liquid LQ2
substantially in parallel to the upper surface T2 of the first
optical element LS1. Therefore, it is possible to avoid the
occurrence of the inconvenience which would be otherwise caused,
for example, such that the first and second optical elements LS1,
LS2 or the like are deformed or displaced due to the supplied
second liquid LQ2.
[0197] A second recovery port 42, which constructs a part of the
second liquid recovery mechanism 40, is provided at a predetermined
position with respect to the second supply port 32 on the inner
side surface PKC of the barrel PK. The second recovery port 42 is
formed at the position in the vicinity of the second space K2 on
the inner side surface PKC of the barrel PK. The second recovery
port 42 is provided on the -X side with respect to the optical axis
AX of the projection optical system PL. That is, the second supply
port 32 and the second recovery port 42 are opposed to each other.
In this embodiment, the second supply port 32 and the second
recovery port 42 are formed to be slit-shaped respectively. The
second supply port 32 and the second recovery port 42 may be formed
to have arbitrary shapes including, for example, substantially
circular, elliptical, and rectangular shapes. In this embodiment,
the second supply port 32 and the second recovery port 42 mutually
have approximately the same size. However, the second supply port
32 and the second recovery port 42 may have sizes different from
each other.
[0198] The other end of the second supply tube 33 is connected to
one end of the second supply flow passage 34 formed in the barrel
PK. On the other hand, the other end of the second supply flow
passage 34 of the barrel PK is connected to the second supply port
32 formed on the inner side surface PKC of the barrel PK. The
second liquid LQ2, which is fed from the second liquid supply
section 31 of the second liquid supply mechanism 30, flows through
the second supply tube 33, and then the second liquid LQ2 flows
into one end of the second supply flow passage 34 formed in the
barrel PK. The second liquid LQ2, which has flown into one end of
the second supply flow passage 34, is supplied to the second space
K2 between the second optical element LS2 and the first optical
element LS1 from the second supply port 32 formed on the inner side
surface PKC of the barrel PK.
[0199] The other end of the second recovery tube 43 is connected to
one end of the second recovery flow passage 44 formed in the barrel
PK. On the other hand, the other end of the second recovery flow
passage 44 is connected to the second recovery port 42 formed on
the inner side surface PKC of the barrel PK. When the second liquid
recovery section 41 of the second liquid recovery mechanism 40 is
driven, the second liquid LQ2 in the second space K2 flows into the
second recovery flow passage 44 via the second recovery port 42.
After that, the second liquid LQ2 is sucked and recovered by the
second liquid recovery section 41 via the second recovery tube
43.
[0200] The barrel PK is provided with an opposing surface 93 which
is opposed to the circumferential edge area of the upper surface T2
of the first optical element LS1 supported by the first support
section 91. A first seal member 94 is provided between the opposing
surface 93 and the circumferential edge area of the upper surface
T2. The first seal member 94 is formed of, for example, a C-ring or
an O-ring (for example, "Kalrez" produced by DuPont Dow). The first
seal member 94 avoids the leakage of the second liquid LQ2 arranged
on the upper surface T2 to the outside of the upper surface T2, and
consequently the leakage to the outside of the barrel PK. A second
seal member 95 is provided between the side surface C2 of the
second optical element LS2 and the inner side surface PKC of the
barrel PK. The second seal member 95 is formed of, for example, a
V-ring. The second seal member 95 regulates the flow of the fluid
(including the gas, the second liquid LQ2, and the humid gas
generated from the second liquid LQ2) between the second space K2
and a third space K3 disposed upwardly from the second optical
element LS2 in the barrel PK. Accordingly, it is possible to
maintain the environment (for example, the temperature and the
humidity) in the internal space of the barrel PK including the
third space K3. Further, it is possible to prevent the gas
(bubble), from the third space K3, from entering into the second
liquid LQ2 of the second liquid immersion area LR2.
[0201] The distance between the side surface C2 of the second
optical element LS2 and the inner side surface PKC of the barrel PK
may be narrowed, for example, to about 1 to 5 .mu.m without
providing the second seal member 95. Also in this way, it is
possible to prohibit the flow of the fluid between the second space
K2 and the third space K3 via the gap between the side surface C2
of the second optical element LS2 and the inner side surface PKC of
the barrel PK.
[0202] When the substrate P is exposed, the control unit CONT
supplies and recovers the second liquid LQ2 by using the second
liquid supply mechanism 30 and the second liquid recovery mechanism
40 while optimally controlling the supply amount of the second
liquid LQ2 per unit time brought about by the second liquid supply
mechanism 30 and the recovery amount of the second liquid LQ2 per
unit time brought about by the second liquid recovery mechanism 40.
And the control unit CONT fills at least the optical path for the
exposure light beam EL in the second space K2 with the second
liquid LQ2. In this embodiment, the second liquid supply mechanism
30 supplies the second liquid LQ2 to the second space K2 at a flow
rate of 0.1 cc/min to 100 cc/min.
[0203] In this embodiment, the supply operation and the recovery
operation for the second liquid LQ2 are continuously performed by
the second liquid supply mechanism 30 and the second liquid
recovery mechanism 40 during the exposure of the substrate P as
well. Further, the supply operation and the recovery operation for
the second liquid LQ2 are continuously performed by the second
liquid supply mechanism 30 and the second liquid recovery mechanism
40 before and after the exposure of the substrate P as well. When
the supply and the recovery of the second liquid LQ2 are
continuously performed by the second liquid supply mechanism 30 and
the second liquid recovery mechanism 40, the second liquid LQ2 in
the second space K2 is always exchanged with the clean and
temperature-managed second liquid LQ2. The second space K2 is
filled with the clean and temperature-managed second liquid LQ2.
When the supply operation and the recovery operation for the second
liquid LQ2 are also continued with respect to the second space K2
before and after the exposure of the substrate P, it is possible to
avoid the occurrence of the inconvenience which would be otherwise
caused, for example, such that any adhesion trace (so-called water
mark) is formed, for example, on the upper surface T2 of the first
optical element LS1 and the lower surface T3 of the second optical
element LS2 resulting from the vaporization (drying) of the second
liquid LQ2.
[0204] Also in the embodiment shown in FIG. 14, the supply and the
recovery of the second liquid LQ2 by the second liquid immersion
mechanism 2 may be performed intermittently. For example, the
supply operation and/or the recovery operation for the liquid by
the second liquid immersion mechanism 2 may be stopped during the
exposure of the substrate P. Accordingly, any vibration, which is
to be caused by the supply and/or the recovery of the second liquid
LQ2, is not generated during the exposure of the substrate P. It is
possible to avoid the deterioration of the exposure accuracy which
would be otherwise caused by the vibration.
[0205] Next, an explanation will be made about another embodiment
of the recovery method with the first liquid recovery mechanism 20
in relation to the embodiments described above. In this embodiment,
only the liquid LQ is recovered from the first recovery port 22.
Accordingly, the occurrence of vibration caused by the liquid
recovery is suppressed.
[0206] The principle of the liquid recovery operation with the
first liquid recovery mechanism 20 of this embodiment will be
explained below with reference to a schematic view shown in FIG.
16. For example, a thin plate-shaped mesh member, which is formed
with a large number of pores, can be used as a porous member 25 for
the first recovery port 22 of the first liquid recovery mechanism
20. In this embodiment, the porous member (mesh member) is formed
of titanium. In this embodiment, only the liquid LQ is recovered
from the pores of the porous member 25 by controlling the pressure
difference between the upper surface and the lower surface of the
porous member 25 so that a predetermined condition is satisfied as
described later on, in a state in which the porous member 25 is
wet. The parameters concerning the predetermined condition include,
for example, the pore size of the porous member 25, the contact
angle (affinity) of the porous member 25 with respect to the liquid
LQ, and the suction force of the first liquid recovery section 21
(pressure at the upper surface of the porous member 25).
[0207] FIG. 16 shows a magnified view illustrating a partial cross
section of the porous member 25, and depicts a specified example of
the liquid recovery to be performed by the aid of the porous member
25. The substrate P is arranged under the porous member 25. The gas
space and the liquid space are formed between the porous member 25
and the substrate P. More specifically, the gas space is formed
between the substrate P and the first pore 25Ha of the porous
member 25, and the liquid space is formed between the substrate P
and the second pore 25Hb of the porous member 25. Such a situation
arises, for example, at the end of the liquid immersion area LR1
shown in FIG. 4, or such a situation arises by the generation of
the gas in the liquid immersion area LR1 due to any cause. A flow
passage space, which forms a part of the first recovery flow
passage 24, is formed over the porous member 25.
[0208] With reference to FIG. 16, when the following condition
holds:
(4.times..gamma..times.cos .theta.)/d.gtoreq.(Pa-Pb) (3)
wherein Pa represents the pressure of the space between the first
pore 25Ha of the porous member 25 and the substrate P (pressure at
the lower surface of the porous member 25), Pb represents the
pressure of the flow passage space over the porous member 25
(pressure at the upper surface of the porous member 25), d
represents the pore size (diameter) of each of the pores 25Ha,
25Hb, .theta. represents the contact angle of the porous member 25
(inside of the pore 25H) with respect to the liquid LQ, and .gamma.
represents the surface tension of the liquid LQ, then, as shown in
FIG. 16, even when the gas space is formed on the lower side of the
first pore 25Ha of the porous member 25 (on the side of the
substrate P), the gas, which is disposed in the space on the lower
side of the porous member 25, can be prevented from any movement to
(entering into) the space disposed on the upper side of the porous
member 25 via the pore 25Ha. That is, the interface between the
liquid LQ and the gas is maintained in the pore 25Ha of the porous
member 25 by optimizing the contact angle .theta., the pore size d,
the surface tension .gamma. of the liquid LQ, and the pressures Pa,
Pb to satisfy the condition represented by the expression (3).
Thus, it is possible to suppress the inflow of the gas from the
first pore 25Ha. On the other hand, the liquid space is formed on
the lower side of the second pore 25Hb of the porous member 25 (on
the side of the substrate P). Therefore, it is possible to recover
only the liquid LQ via the second pore 25Hb.
[0209] In the case of the condition represented by the expression
(3) described above, the hydrostatic pressure of the liquid LQ on
the porous member 25 is not considered in order to simplify the
explanation.
[0210] In this embodiment, the first liquid recovery mechanism 20
controls the suction force of the first liquid recovery section 21
to adjust the pressure of the flow passage space over the porous
member 25 so that the expression (3) described above is satisfied,
assuming that the pressure Pa of the space under the porous member
25, the diameter d of the pore 25H, the contact angle .theta. of
the porous member 25 (inner side surface of the pore 25H) with
respect to the liquid LQ, and the surface tension .gamma. of the
liquid (pure water) LQ are constant. However, with reference to the
expression (3), as (Pa-Pb) is greater, i.e., as
(4.times..gamma..times.cos .theta.)/d is greater, the pressure Pb
is more easily controlled to satisfy the expression (3). Therefore,
it is desirable that the diameter d of the pore 25Ha, 25Hb and the
contact angle .theta. of the porous member 25 with respect to the
liquid LQ (0.degree.<.theta.<90.degree.) are made as small as
possible.
[0211] In the embodiments described above, the projection optical
system PL is provided with the element as the first optical element
LS1 in which the outer diameter of the upper surface T2 is wider
than that of the lower surface T3 of the second optical element
LS2. However, in order to achieve the formation of the liquid
immersion area in only the partial area of the upper surface
(second surface) of the first optical element (first element) as in
the first embodiment of the present invention, it is also allowable
that the outer diameter of the lower surface T3 of the second
optical element LS2 is wider than that of the upper surface T2 of
the first optical element LS1. In this arrangement, for example,
the outer edge portion of the lower surface T3 of the second
optical element LS2 can be treated to be liquid-repellent, and only
the central portion for forming the liquid immersion area can be
treated to be liquid-attractive. Alternatively, a bank DR as shown
in FIG. 10 may be provided at the outer edge portion of the lower
surface T3 of the second optical element LS2.
[0212] In the embodiments shown in FIGS. 1 to 14 and FIG. 16, it is
not necessarily indispensable that the supply operation and the
recovery operation for the second liquid LQ2 performed by the
second liquid supply mechanism 30 and the second liquid recovery
mechanism 40 are the same as the supply operation and the recovery
operation for the first liquid LQ1 performed by the first liquid
supply mechanism 10 and the first liquid recovery mechanism 20. It
is also allowable that the supply amount and the recovery amount of
each of the liquids and/or the flow rate of each of the liquids is
different from each other. For example, the supply amount and the
recovery amount of the liquid LQ2 in the second space K2 may be
smaller than the supply amount and the recovery amount of the first
liquid LQ1 in the first space, and the flow rate of the liquid LQ2
in the second space K2 may be slower than the flow rate of the
liquid LQ1 in the first space K1.
[0213] In the embodiment described above, the liquid (pure water),
which is supplied from the first liquid supply mechanism 10 to the
first space K1, is the same as the liquid (pure water) which is
supplied from the second liquid supply mechanism 30 to the second
space K2 (temperature is the same as well). However, even when the
type of the liquid is identical, the quality (for example, the
temperature, the temperature uniformity, and the temperature
stability) may differ. For example, when pure water is used as in
the embodiment described above, the specific resistance value, the
total organic carbon (TOC) value, and the dissolved gas
concentration (dissolved oxygen concentration, dissolved nitrogen
concentration), the refractive index, and the transmittance may
differ, for example, in addition to the temperature, the
temperature uniformity, and the temperature stability.
[0214] As described above, pure water is used as the liquid LQ1,
LQ2 in the embodiment of the present invention. Pure water is
advantageous in that pure water is available in a large amount with
ease, for example, in the semiconductor production factory, and
pure water exerts no harmful influence, for example, on the optical
element (lens) and the photoresist on the substrate P. Further,
pure water exerts no harmful influence on the environment, and the
content of impurity is extremely low. Therefore, it is also
expected to obtain the function to wash (clean) the surface of the
substrate P and the surface of the optical element provided at the
end surface of the projection optical system PL. When the purity of
pure water supplied from the factory or the like is low, the
exposure apparatus may posses an ultrapure water-producing
unit.
[0215] It is approved that the refractive index n of pure water
(water) with respect to the exposure light beam EL having a
wavelength of about 193 nm is approximately in an extent of 1.44.
When the ArF excimer laser beam (wavelength: 193 nm) is used as the
light source of the exposure light beam EL, then the wavelength is
shortened on the substrate P by 1/n, i.e., to about 134 nm, and a
high resolution is obtained. Further, the depth of focus is
magnified about n times, i.e., about 1.44 times as compared with
the value obtained in the air. Therefore, when it is enough to
secure an approximately equivalent depth of focus as compared with
the case of the use in the air, it is possible to further increase
the numerical aperture of the projection optical system PL. Also in
this viewpoint, the resolution is improved.
[0216] In the embodiment described above, the first and second
liquid supply mechanisms 10, 30 supply pure water as the liquids
LQ1, LQ2. However, mutually different types of liquids may be
supplied so that the first liquid LQ1, with which the first space
K1 is filled, may be of the type different from that of the second
liquid LQ2 with which the second space K2 is filled. In this case,
it is also allowable that the refractive index and/or the
transmittance with respect to the exposure light beam EL differs
between the first liquid and the second liquid. For example, the
second space K2 may be filled with a predetermined liquid other
than pure water, which is represented by fluorine-based oil. The
oil is such a liquid that the probability of proliferation of
microbes such as bacterial is low. Therefore, it is possible to
maintain the cleanness of the second space K2 and the flow passage
through which the second liquid LQ2 (fluorine-based oil) flows.
[0217] Both of the first and second liquids LQ1, LQ2 may be liquids
other than water. For example, when the light source of the
exposure light beam EL is the F.sub.2 laser, the F.sub.2 laser beam
is not transmitted through water. Therefore, it is preferable to
use a fluorine-based liquid including, for example,
perfluoropolyether (PFPE) and fluorine-based oil through which the
F.sub.2 laser beam is transmissive, as the first and second liquid
LQ1, LQ2. In this case, the portion, which makes contact with the
first and second liquid LQ1, LQ2, is subjected to the
liquid-attracting treatment, for example, by forming a thin film
with a substance having a molecular structure with small polarity
including fluorine. Alternatively, other than the above, it is also
possible to use, as the first and second liquid LQ1, LQ2, liquids
(for example, cedar oil) which have the transmittance with respect
to the exposure light beam EL, which have the refractive index as
high as possible, and which are stable against the photoresist
coated on the surface of the substrate P and the projection optical
system PL. Also in this case, the surface treatment is performed
depending on the polarity of the first and second liquid LQ1, LQ2
to be used. It is also possible to use various types of fluids
having desired refractive indexes, including, for example,
supercritical fluids and gases having high refractive indexes, in
place of pure water for the liquids LQ1, LQ2.
[0218] In the embodiment described above, the projection optical
system PL, which includes the first optical element LS1 as the
parallel flat plate having no refractive power, is adjusted to have
the predetermined image formation characteristic. However, when the
first optical element LS1 exerts no influence on the image
formation characteristic at all, it is also allowable to make the
adjustment so that the image formation characteristic of the
projection optical system PL is the predetermined image formation
characteristic except for the first optical element LS1.
[0219] In the embodiment described above, both of the first optical
element LS1 and the second optical element LS2 are supported by the
barrel PK. However, the first optical element LS1 and the second
optical element LS2 may be supported by different support members
respectively.
[0220] In the embodiment described above, both of the first optical
element LS1 and the second optical element LS2 are supported by the
barrel PK in the substantially stationary state. However, the first
optical element LS1 and the second optical element LS2 may be
supported finely movably in order to adjust the position and the
posture of at least one of the first optical element LS1 and the
second optical element LS2.
[0221] In the embodiment described above, the first optical element
LS1 is the parallel flat plate having no refractive power in which
the lower surface T1 and the upper surface T2 are the flat surfaces
respectively, and the lower surface T1 and the upper surface T2 are
in parallel to each other. However, for example, the upper surface
T2 of the first optical element LS1 may have a slight curvature.
That is, the first optical element LS1 may be an optical element
having any lens function. In this case, it is preferable that the
curvature of the upper surface T2 of the first optical element LS1
is smaller than the curvatures of the upper surface T4 and the
lower surface T3 of the second optical element LS2.
[0222] In the embodiment described above, it is also allowable that
the second liquid immersion mechanism 2 for performing the supply
and the recovery of the second liquid LQ2 is absent. In this case,
the exposure is performed without exchanging the second liquid LQ2
in the second space K2 in the state in which the space between the
first optical element LS1 and the second optical element LS2 is
filled with the second liquid LQ2. In such a situation, there is
such a possibility that the temperature of the second liquid LQ2 in
the second liquid immersion area LR2 may be varied by the radiation
of the exposure light beam EL. Therefore, a temperature-adjusting
unit, which adjusts the temperature of the second liquid LQ2 in the
second liquid immersion area LR2, may be provided, for example,
between the first optical element LS1 and the second optical
element LS2 to successfully adjust the temperature of the second
liquid LQ2 by using the temperature-adjusting unit. The respective
embodiments described above are principally illustrative of the
case in which the projection optical system PL and the substrate P
are opposed to one another. However, even when the projection
optical system PL is opposed to another member (for example, the
upper surface 91 of the substrate stage PST), the space between the
projection optical system PL and the another member can be filled
with the first liquid LQ1. In this arrangement, the space on the
image plane side of the projection optical system PL may be
continuously filled with the first liquid LQ1 by using the another
member when the substrate stage PST is separated from the
projection optical system PL, for example, during the operation for
exchanging the substrate.
[0223] In the case of the liquid immersion method as described
above, the numerical aperture NA of the projection optical system
is 0.9 to 1.3 in some cases. When the numerical aperture NA of the
projection optical system is large as described above, it is
desirable to use the polarized illumination, because the image
formation performance is deteriorated due to the polarization
effect in some cases with the random polarized light which has been
hitherto used as the exposure light beam. In this case, it is
appropriate that the linear polarized illumination, which is
adjusted to the longitudinal direction of the line pattern of the
line-and-space pattern of the mask (reticle), is effected so that
the diffracted light of the S-polarized light component
(TE-polarized light component), i.e., the component in the
polarization direction along with the longitudinal direction of the
line pattern is dominantly allowed to outgo from the pattern of the
mask (reticle). When the space between the projection optical
system PL and the resist coated on the surface of the substrate P
is filled with the liquid, the diffracted light of the S-polarized
light component (TE-polarized light component), which contributes
to the improvement in the contrast, has the high transmittance on
the resist surface, as compared with the case in which the space
between the projection optical system PL and the resist coated on
the surface of the substrate P is filled with the air (gas).
Therefore, it is possible to obtain the high image formation
performance even when the numerical aperture NA of the projection
optical system exceeds 1.0. Further, it is more effective to
appropriately combine, for example, the phase shift mask and the
oblique incidence illumination method (especially the dipole
illumination method) adjusted to the longitudinal direction of the
line pattern as disclosed in Japanese Patent Application Laid-open
No. 6-188169. In particular, the combination of the linear
polarized illumination method and the dipole illumination method is
effective when the direction of the cycle of the line-and-space
pattern is limited to a predetermined certain direction and/or when
the hole pattern is clustered in a predetermined certain direction.
For example, when a phase shift mask of the half tone type having a
transmittance of 6% (pattern of a half pitch of about 45 nm) is
illuminated by using the linear polarized illumination method and
the dipole illumination method in combination, the depth of focus
(DOF) can be increased by about 150 nm as compared with a case in
which the random polarized light beam is used, provided that the
illumination .sigma., which is defined by the circumscribed circle
of the two light fluxes for forming the dipole at the pupil plane
of the illumination system, is 0.95, the radius of each light flux
at the pupil plane is 0.125.sigma., and the numerical aperture of
the projection optical system PL is NA=1.2.
[0224] For example, when the ArF excimer laser is used as the
exposure light beam, and the substrate P is exposed with a fine
line-and-space pattern (for example, line-and-space of about 25 to
50 nm) by using the projection optical system PL having a reduction
magnification of about 1/4, then the mask M acts as a polarizing
plate due to the Wave guide effect depending on the structure of
the mask M (for example, the pattern fineness and the thickness of
chromium), and the diffracted light of the S-polarized light
component (TE-polarized light component) outgoes from the mask M in
an amount greater than that of the diffracted light of the
P-polarized light component (TM-polarized light component) which
lowers the contrast. In this case, it is desirable to use the
linear polarized illumination as described above. However, even
when the mask M is illuminated with the random polarized light, it
is possible to obtain the high resolution performance even when the
numerical aperture NA of the projection optical system PL is large,
for example, 0.9 to 1.3.
[0225] When the substrate P is exposed with an extremely fine
line-and-space pattern on the mask M, there is such a possibility
that the P-polarized light component (TM-polarized light component)
is greater than the S-polarized light component (TE-polarized light
component) due to the Wire Grid effect. However, for example, when
the ArF excimer laser is used as the exposure light beam, and the
substrate P is exposed with a line-and-space pattern greater than
25 nm by using the projection optical system PL having a reduction
magnification of about 1/4, then the diffracted light of the
S-polarized light component (TE-polarized light component) outgoes
from the mask M in an amount greater than that of the diffracted
light of the P-polarized light component (TM-polarized light
component). Therefore, it is possible to obtain the high resolution
performance even when the numerical aperture NA of the projection
optical system PL is large, for example, 0.9 to 1.3.
[0226] Further, it is also effective to use the combination of the
oblique incidence illumination method and the polarized
illumination method in which the linear polarization is effected in
the tangential (circumferential) direction of the circle having the
center of the optical axis as disclosed in Japanese Patent
Application Laid-open No. 6-53120, without being limited only to
the linear polarized illumination (S-polarized illumination)
adjusted to the longitudinal direction of the line pattern of the
mask (reticle). In particular, when the pattern of the mask
(reticle) includes not only the line pattern extending in one
predetermined direction, but the pattern also includes the line
patterns extending in a plurality of different directions in a
mixed manner (line-and-space patterns having different directions
of the cycle are present in a mixed manner), then it is possible to
obtain the high image formation performance even when the numerical
aperture NA of the projection optical system is large, by using, in
combination, the zonal illumination method and the polarized
illumination method in which the light is linearly polarized in the
tangential direction of the circle having the center of the optical
axis, as disclosed in Japanese Patent Application Laid-open No.
6-53120 as well. For example, when a phase shift mask of the half
tone type having a transmittance of 6% (pattern of a half pitch of
about 63 nm) is illuminated by using, in combination, the zonal
illumination method (zonal ratio: 3/4) and the polarized
illumination method in which the light is linearly polarized in the
tangential direction of the circle having the center of the optical
axis, the depth of focus (DOF) can be increased by about 250 nm as
compared with a case in which the random polarized light beam is
used, provided that the illumination .sigma. is 0.95, and the
numerical aperture of the projection optical system PL is NA=1.00.
In the case of a pattern having a half pitch of about 55 nm with a
numerical aperture NA=1.2 of the projection optical system, the
depth of focus can be increased by about 100 nm.
[0227] The substrate P, which is usable in the respective
embodiments described above, is not limited to the semiconductor
wafer for producing the semiconductor device. Substrates applicable
include, for example, the glass substrate for the display device,
the ceramic wafer for the thin film magnetic head, and the master
plate (synthetic silica glass, silicon wafer) for the mask or the
reticle to be used for the exposure apparatus. In the embodiments
described above, the light-transmissive type mask (reticle), in
which the predetermined shielding pattern (or the phase pattern or
the dimming pattern) is formed on the light-transmissive substrate,
is used. However, in place of the reticle, it is also allowable to
use an electronic mask for forming a transmissive pattern, a
reflective pattern, or a light emission pattern on the basis of the
electronic data of the pattern to be subjected to the exposure, as
disclosed, for example, in U.S. Pat. No. 6,778,257. The present
invention is also applicable to an exposure apparatus (lithography
system) in which a line-and-space pattern is formed on a wafer W by
forming interference fringes on the wafer W, as disclosed in the
pamphlet of International Publication No. 2001/035168.
[0228] As for the exposure apparatus EX, the present invention is
also applicable to the scanning type exposure apparatus (scanning
stepper) based on the step-and-scan system for performing the
scanning exposure for the pattern of the mask M by synchronously
moving the mask M and the substrate P as well as the projection
exposure apparatus (stepper) based on the step-and-repeat system
for performing the full field exposure with the pattern of the mask
M in a state in which the mask M and the substrate P are allowed to
stand still, while successively step-moving the substrate P.
[0229] As for the exposure apparatus EX, the present invention is
also applicable to the exposure apparatus of the system in which
the substrate P is subjected to the full field exposure by using a
projection optical system (for example, a dioptric type projection
optical system including no catoptric element with a reduction
magnification of 1/8) with a reduction image of a first pattern in
a state in which the first pattern and the substrate P are allowed
to substantially stand still. In this case, the present invention
is also applicable to the full field exposure apparatus based on
the stitch system in which, subsequent to the exposure operation
for the first pattern as described above, the substrate P is
subjected to the full field exposure while partially overlaying a
reduction image of a second pattern on the first pattern by using
the projection optical system in a state in which the second
pattern and the substrate P are allowed to substantially stand
still thereafter. As for the exposure apparatus based on the stitch
system, the present invention is also applicable to the exposure
apparatus based on the step-and-stitch system in which at least two
patterns are partially overlaid and transferred on the substrate P,
and the substrate P is successively moved. The present invention is
also applicable to an exposure apparatus provided with a measuring
stage which includes members and sensors for the measurement
separately from the stage which holds the substrate P. The exposure
apparatus provided with the measuring stage is described, for
example, in European Patent Publication No. 1,041,357, contents of
which are incorporated herein by reference within a range of
permission of the domestic laws and ordinances of the state
designated or selected in this international application.
[0230] The present invention is also applicable to the twin-stage
type exposure apparatus. The structure and the exposure operation
of the twin-stage type exposure apparatus are disclosed, for
example, in Japanese Patent Application Laid-open Nos. 10-163099
and 10-214783 (corresponding to U.S. Pat. Nos. 6,341,007,
6,400,441, 6,549,269, and 6,590,634), Published Japanese
Translation of PCT International Publication for Patent Application
No. 2000-505958 (corresponding to U.S. Pat. No. 5,969,441), and
U.S. Pat. No. 6,208,407, contents of which are incorporated herein
by reference within a range of permission of the domestic laws and
ordinances of the state designated or selected in this
international application.
[0231] In the embodiment described above, the exposure apparatus,
in which the space between the projection optical system PL and the
substrate P is locally filled with the liquid, is adopted. However,
the present invention is also applicable to the liquid immersion
exposure apparatus in which the entire surface of the substrate as
the exposure objective is covered with the liquid. The structure
and the exposure operation of the liquid immersion exposure
apparatus in which the entire surface of the substrate as the
exposure objective is covered with the liquid are described in
detail, for example, in Japanese Patent Application Laid-open Nos.
6-124873 and 10-303114 and U.S. Pat. No. 5,825,043, contents of
which are incorporated herein by reference within a range of
permission of the domestic laws and ordinances of the state
designated or selected in this international application.
[0232] As for the type of the exposure apparatus EX, the present
invention is not limited to the exposure apparatus for the
semiconductor device production for exposing the substrate P with
the semiconductor device pattern. The present invention is also
widely applicable, for example, to the exposure apparatus for
producing the liquid crystal display device or for producing the
display as well as the exposure apparatus for producing, for
example, the thin film magnetic head, the image pickup device
(CCD), the reticle, or the mask.
[0233] When the linear motor is used for the substrate stage PST
and/or the mask stage MST, it is allowable to use any one of those
of the air floating type based on the use of the air bearing and
those of the magnetic floating type based on the use of the
Lorentz's force or the reactance force. Each of the stages PST, MST
may be either of the type in which the movement is effected along
the guide or of the guideless type in which no guide is provided.
An example of the use of the linear motor for the stage is
disclosed in U.S. Pat. Nos. 5,623,853 and 5,528,118, contents of
which are incorporated herein by reference respectively within a
range of permission of the domestic laws and ordinances of the
state designated or selected in this international application.
[0234] As for the driving mechanism for each of the stages PST,
MST, it is also allowable to use a plane motor in which a magnet
unit provided with two-dimensionally arranged magnets and an
armature unit provided with two-dimensionally arranged coils are
opposed to one another, and each of the stages PST, MST is driven
by the electromagnetic force. In this arrangement, any one of the
magnet unit and the armature unit is connected to the stage PST,
MST, and the other of the magnet unit and the armature unit is
provided on the side of the movable surface of the stage PST,
MST.
[0235] The reaction force, which is generated in accordance with
the movement of the substrate stage PST, may be mechanically
released to the floor (ground) by using a frame member so that the
reaction force is not transmitted to the projection optical system
PL. The method for handling the reaction force is disclosed in
detail, for example, in U.S. Pat. No. 5,528,118 (Japanese Patent
Application Laid-open No. 8-166475), contents of which are
incorporated herein by reference within a range of permission of
the domestic laws and ordinances of the state designated or
selected in this international application.
[0236] The reaction force, which is generated in accordance with
the movement of the mask stage MST, may be mechanically released to
the floor (ground) by using a frame member so that the reaction
force is not transmitted to the projection optical system PL. The
method for handling the reaction force is disclosed in detail, for
example, in U.S. Pat. No. 5,874,820 (Japanese Patent Application
Laid-open No. 8-330224), contents of which are incorporated herein
by reference within a range of permission of the domestic laws and
ordinances of the state designated or selected in this
international application.
[0237] As described above, the exposure apparatus EX according to
the embodiment of the present invention is produced by assembling
the various subsystems including the respective constitutive
elements as defined in claims so that the predetermined mechanical
accuracy, the electric accuracy, and the optical accuracy are
maintained. In order to secure the various accuracies, those
performed before and after the assembling include the adjustment
for achieving the optical accuracy for the various optical systems,
the adjustment for achieving the mechanical accuracy for the
various mechanical systems, and the adjustment for achieving the
electric accuracy for the various electric systems. The steps of
assembling the various subsystems into the exposure apparatus
include, for example, the mechanical connection, the wiring
connection of the electric circuits, and the piping connection of
the air pressure circuits in correlation with the various
subsystems. It goes without saying that the steps of assembling the
respective individual subsystems are performed before performing
the steps of assembling the various subsystems into the exposure
apparatus. When the steps of assembling the various subsystems into
the exposure apparatus are completed, the overall adjustment is
performed to secure the various accuracies as the entire exposure
apparatus. It is desirable that the exposure apparatus is produced
in a clean room in which, for example, the temperature and the
cleanness are managed.
[0238] As shown in FIG. 15, the microdevice such as the
semiconductor device is produced by performing, for example, a step
201 of designing the function and the performance of the
microdevice, a step 202 of manufacturing a mask (reticle) based on
the designing step, a step 203 of producing a substrate as a base
material for the device, an exposure process step 204 of exposing
the substrate with a pattern of the mask by using the exposure
apparatus EX of the embodiment described above, a step 205 of
assembling the device (including a dicing step, a bonding step, and
a packaging step), and an inspection step 206.
INDUSTRIAL APPLICABILITY
[0239] According to the present invention, it is possible to avoid
the deterioration of the exposure accuracy and the measurement
accuracy which would be otherwise caused by the pollution of the
element (optical element). Therefore, the exposure process and the
measurement process can be performed accurately. Further, according
to the present invention, it is possible to realize the compact
size of the apparatus itself, because the liquid immersion area can
be made small.
* * * * *